Can you buy a luxury car with cash? Let's say, hypothetically, you try buying a luxury car or expensive jewelry using cash (100 dollar bills in a bag!). Would that be legal? Will IRS or FBI or anybody come knocking on the door asking about origin of that money or its taxes or whatever?
You can purchase any expensive item for cash, if the seller will accept it. In the US and many other jurisdictions, a seller is not required to accept cash, but many will. In the US and many other jurisdictions banks are required to report large cash deposits to government authorities, to help combat money-laundering, drug-dealing, and tax-evasion. Such a report may trigger an investigation, and during that investigation a person who bought an expensive item for cash may well be asked about the source of the cash. Whether an answer is legally required will depend on the law in the particular place. But even if it is not legally required, refusing to answer such questions may trigger additional investigation.
at what point can you just leave? Is it always technically illegal in the UK to leave without paying the bill? Probably depends on what you mean with just leaving. If just leaving translates I haven't paid and I won't pay (because of the hassle with the card) then that's probably Making Off Without Payment, section 3 Theft Act 1978 (Thanks @bdsl). Could the restaurant just force you to wait until close of business if necessary? What if they still hadn't fixed the payment system by then? I don't think a restaurant can physically detain you. Not even the 45 min you have been waiting. But if you leave without paying and without an agreement with them how &amp; when to pay they can of course call the police because again that looks very much like making off without payment. According to your post, they did provide a payment system (cash) which was working all the time and that moreover has the special status of being legal tender. if you don't physically have the cash on you, you can be sued? You can be sued if you don't pay your bill (assuming the bill itself is correct) when it's due. In order to avoid endless hassle of the "I tried to pay via x, but they wouldn't accept this." type, legal tender defines ways of payment of a debt that the creditor/seller must accept. In many legislations, cash in the local currency provides such a fallback if other payment methods fail. Note that cash payment is very robust against internet failure, broken devices and power The UK (+ US) meaning of legal tender is that the restaurant must accept this means of settling the debt (at this time, the food is already eaten but not payed) - but they don't have to accept any other means of payment. (Note that e.g. for the EUR-countries there is at least a recommendation to make acceptance of legal tender mandatory also in retail, which includes simultaneous exchange food vs. payment). The 2nd important implication of this is that any argumentation along the lines that no reasonable means of payment were available would be very weak. You are not required to have sufficient cash with you to pay your bill if you can reasonably assume that some other way of payment will be acceptable to the restaurant. I see that like a spare wheel for a car: if you have a flat tire (card doesn't work) having a spare wheel (cash) allows you to deal with the issue with less hassle than if you don't: change your wheel vs. having to get your car brought to a workshop and wait until they put on a new tire (pay cash instead of waiting for the card to work again or a tedious hunt for another payment method). I'd like to point out that card doesn't work and not sufficient cash at hand (or forgotten purse) is something that happens quite often in general (rarely for any given transaction, but we have lots of transactions). I'd expect a restaurant or a gas station to be experienced in dealing with that. In any case, there are several possibilities to resolve the issue short of "just leaving": The key to all this is communication: talk to the restaurant to find a way to resolve the issue. Reassure them that you're not trying to use the opportunity to defraud them - that's what they are afraid of in this situation. "Where can I find an ATM?" Possibly offering a deposit: "And would you mind looking after my bag [phone] until I'm back?" Possibly showing them your ID card (or similar, if you have any) so they have your address: remember that so far you are an anonymous customer for them: which means that suing you for the money would be somewhere between too expensive and impossible. If you are a group, it should be sufficient if only one of you leaves in search of cash. Credit cards can be charged in a total offline way (MOTO = mail order/telephone order) where the credit card data is entered manually by the seller: the restaurant may be able to charge your credit card if fill in a paper credit card payment form. They may accept settlement via other payment systems: paypal &amp; Co. wire the money via your online banking account (even if that doesn't give an instantaneous transfer, ask them if that's OK with them if you show/forward them the "transfer accepted message" for now) allow them to withdraw the money from your account via direct debit or something similar I'd not expect a restaurant to accept this possibility as they're probably not familiar with it and it means a lot of hassle for them with their bank to get listed to receive money that way. if you are in a region where cheques are still in regular use, that may be a solution as well. Restaurants like any other business can write invoices. They usually don't like this because their risk of having costly trouble to get the money is high. While your printout bill is technically an invoice already, it can be turned into an invoice (+ copy for them) giving your name + address and specifying how and when you'll pay. Which would keep track of how you (pl. = you + restaurant) decided to settle the bill under the peculiar circumstances. This works even in case of e.g. a power outage that prevents you from getting cash from an ATM in the neighborhood.
A receipt is just a written proof that money was taken. It is hard to imagine a place on Earth where the legality of giving such a proof would be questionable at all so that you would need to talk about an "authority to issue receipts". Only if you find a place where money itself is illegal. Now, the real question here is whether such receipts (issued by private persons not registered as businesses) can be used for accounting purposes, e.g. to claim that your business, which transacted with those persons, incurred expenses. The mere fact that sole traders need to be registered to do business does not outlaw the use of receipts issued by non-registered persons. For example, your business could be buying old stuff from the public (used cars, electronics etc.) and refurbishing it. Provided that this activity itself is not illegal, receiving receipts from those one-off private sellers, and using them in your bookkeeping would be perfectly legal too.
Two people exchanging goods or services on a commercial basis and then pretending it was two gifts is tax evasion. It's not a gift. It's a commercial sale that you lie about by 'putting' a different 'label' on it. Sometimes two people will give mutual gifts, e.g. if you come to my wedding: I give you dinner, you give me some kitchenware. Yet there's nothing commercial about it. So that's not income for either party. However, if you're talking about two businesses making sales to each other, that is very much income, regardless of what you badge it.
Nobody know what constitutes "scamming", because it's not a legal concept. There is no sense in which receiving a gift itself constitutes "scamming". Since scamming is vaguely about dishonesty, there is an imaginable scenario where you could be liable for a false representation, for example if you impersonated someone else in order to receive something of value, you could be prosecuted in California. You should not assume that a police officer saying "That's not our problem" is proof that you committed no crime or civil tort. Your lawyer can give you advice as to whether you have anything to worry about, legally. The other stuff about being called a scammer or having pictures posted might be a violation of Facebook's TOS, and you can always complain to Facebook central authorities. Technically, uploading a picture that someone took is a violation of copyright law, if you didn't give permission to do so. It might run afoul of some state~provincial or national privacy law, depending on where this takes place.
Since you asked, and it's a perfectly legitimate question, here's why it doesn't violate the Fifth Amendment (from Garner v. US): The Fifth Amendment doesn't say "you can't be made to say anything that hurts you." It says "no person...shall be compelled in any criminal case to be a witness against himself." The only time Fifth Amendment protection applies is if you are being forced by the government to make a statement that could open you up to an accusation or conviction of a criminal offense. It's fairly broad (if it would help prove any aspect of the charge, you can claim immunity), but it's also restricted (you can't claim it unless it really would tend to incriminate you). That means that you could only argue the Fifth Amendment if your tax return might help prove a criminal case against you (the fact that disclosing income leads to you needing to pay tax does not qualify as "self-incrimination"). But the amount of income is not one of those things that might incriminate you -- you can get income through all sorts of ways. The thing that is incriminating is revealing the source of the income, and you can claim Fifth Amendment privilege for that. So: The only time you could possibly claim privilege is if you were being forced into a statement that might tend to incriminate you in a criminal proceeding. A statement that makes you liable for tax doesn't mean it might incriminate you. Filing an income tax return isn't inherently incriminating. The fact that you have income not included in any other part of the return (illegal income goes under "other income") doesn't imply you've committed a crime -- lots of people have other income. The amount of income can't be incriminating. The source can be, but you can claim Fifth Amendment privilege for that if it might incriminate you. And lawful income under "other income" still might give rise to a reasonable fear of prosecution, so the fact that you're justified in claiming Fifth Amendment privilege in source of income doesn't mean you're guilty of a crime. Note that there are cases where you are flat-out exempt from filing tax returns under the Fifth Amendment: Marchetti v. US and Grosso v. US found that registration and tax on gambling could be blocked by a Fifth Amendment claim, which didn't even have to be asserted at time of filing, because merely filing the special return would establish you as a gambler (heavily regulated/often criminalized at the state level). The difference with the normal income tax form is that everyone (just about) files one, and so filing it doesn't mean you're a criminal. If there was a separate line along the lines of "Income from Illegal Drug Sales," that might be one thing (anything other than $0 is inherently incriminating). But all the questions are broad, and have many legal sources of income associated with them.
In theory its only a crime if you know, or reasonably suspect, that it is stolen. The fact that you have to ask means that you have some level of suspicion, so that's not good to start with. In practice merely being investgated by the police will bring you a world of hurt long before it gets to trial. How much can you afford to spend on legal fees, and will you be able to make bail?
If it looks like a gift and sounds like a gift and there is no evidence that it should not be considered a gift, well, what else could it be? Given the value of a house and depending on jurisdiction, there may be a gift tax involved. This is normally an obligation placed on the giver, not the receiver. It is unlikely to be a concern to you but a separate check would be wise for your own sake. If all ownership documents are clear that you and you alone own (and pay regular costs of, and maintain) the house, it is extremely unlikely that any private individual can take it away from you, regardless of their relationship to you. There doesn't appear to be any legal basis for their claims; they are hoping you will bow to social and emotional pressure. Your best course of action is to call their bluff. Request a written statement (ideally through their lawyer) that identifies the reason for their claims of ownership or otherwise why the property should be transferred to them (ideally checked by your lawyer) and proceed from your lawyer's advice.