What is the point of signatures? Signing a document to show your agreement is very common, but signatures seem very easy to forge. Nowadays, with electronic signatures it is trivial - some software doesn't even include your actual signature but pastes in your name in a cursive font. What good does it do to sign something, then? Couldn't you just claim you didn't sign anything afterwards?
The issues you describe have existed with signatures from the beginning of their use. There exists a tradeoff between ease of use and reliability, both of forgery and of people falsely claiming forgery. Originally, the closest thing to a signature was the use of seals and signet rings. While relatively hard to forge, it only showed that the possessor of the object agreed. Signatures, especially in cursive font, were developed later. They were in some ways easier to forge(you didn't need to get access to a physical device), but more difficult in others(the seal symbols tended to be used on everything and various improvements in technology had been made), and harder to falsely claim forgery(because most people can't alter their handwriting well). You were affixing your name to the document, indicating that you agreed. Often, the signatures were required to backed up with the signatures of other people as witnesses. They didn't have to agree to the document, they just had to agree to testify that you signed of your own free will. Because witnesses, especially trustworthy and independent witnesses, are hard to come by, some places have dropped that requirement, such as checks and signing a aper receipt when using a credit card. But for some important documents, certain jurisdictions still require witnesses, including large transactions (a document relating to a car insurance payout I recently had required a witness to confirm my signature) and marriages. However, with electronic media, the point of a signature is more to indicate deliberate acceptance of terms, with verification of an individual being left to other processes (e.g. IP address, MAC address, linkage to a specific email account, etc.), so forgery is less of an issue. I have also seen "signatures" amount to checkboxes and "I agree" buttons. Generally, the higher the stakes and "more legal" the agreement, the more likely to these have been the "typed signatures" that you describe, but this seems to be decreasing in frequency, suggesting that its purpose was to stop gap a hole in legal acceptance by judges/courts/laws with regards to electronic communications. Addendum: It should also note that the replacement of seals by signatures is not universal; for instance in Japan, seals are still used over signatures in the majority of cases.
IMHO, your questions reflect several misunderstandings of how the process works. So, with your permission, I will avoid directly answering your questions and instead focus on suggestions how to best help you plot a path forward. Your counterparty has the burden of proof. If your counterparty forged your signature on a contract, then they must prove you signed it or they can not enforce it. In order to enforce the contract, they will need to sue you civilly. Then you can introduce evidence of their forgery at that time. Inform your counterparty you did not sign the contract. Then act accordingly. If your counterparty forged your signature on an extension contract then you should inform them immediately after it has come to your attention. Advise them you have no intention of complying with a contract you never signed. And that if they try to enforce the forged agreement, you will defend yourself "vigorously." Never threaten criminal charges to advance your position in a civil case. This behavior is a crime in itself. It's called extortion. If you want to pursue criminal charges at some point then do it without relating it to the civil case. The police are not your only means of pursuing criminal charges. You can also schedule a meeting with your District Attorney, State's Attorney (whatever that position is called in your state) or your state's Attorney General. In other words, you might want to approach the government's attorney responsible for prosecuting crimes in your jurisdiction. Forget about involving the police. They have given you their position on the matter. Approach the DA or AG office instead. If the DA/AG decides to use the police, she we will make that decision then inform the police how she needs to use their services. Police are wary of being used as leverage in civil disputes. That's probably the reason for their policy decision regardless of whether it's technically justified by the law or not. Your counterparty can't "fix" anything. If they claim you signed a document you did not, they will have to produce that document with your signature on it. This will presumably be your Exhibit A evidence they forged it. Disclaimer: I am a lay person and not an attorney. This writing is no substitute for proper legal advice. If you need help with a specific legal situation please hire an attorney and do not rely on anything I have written here.
From a legal perspective co-signing a loan isn't the same thing loaning the money to the other co-signer. When you co-sign a loan with someone else both you and the other person are equal parties in the loan, both jointly responsible in fully paying off the principle and interest. If loan is defaulted on, the bank can pursue legal remedies to try to recover its money against either or both of you. If you end up having to pay part or all of the loan, then whether or not you can recover any of that money will depend on whatever agreement you made with the other person. Given that you probably wouldn't a have a signed written agreement with the other signer in case like this, it'll probably come down to whether or not you can prove (on the balance of probabilities) that the other party promised to you to pay off the full amount of the loan. It will help if the loan is specifically tied to a car, a house or other property that the other party benefits from but you don't. Note that you'd have to give serious consideration to whether the other party can actually pay the amount owed. There's no point going to court to obtain an unenforceable judgement. I also should say that from a financial perspective it does make some sense to think of it as if you were loaning out the money yourself. While there's a big and significant difference between the two, in that your bank account isn't affected unless the other person defaults, if they do the result is going to be pretty much the same. Indeed in that case it's not much different than just giving the other person the money. When co-signing a loan you really need to trust that other person.
You can read about Magnuson Moss here, but it only applies to warranties on goods, not services. As you note, the warranty on the unit is still valid. As for agreeing, it is not unusual that a consumer is not aware what all they are agreeing to when they buy a house. One of those myriad signatures that you put on myriad documents was your agreement to contract terms in the pile of papers that you were handed. If you trace through the entire pile of pieces of paper, you should find something saying that you agree to &quot;all of the attached conditions&quot;, which is where you are supposed to say &quot;Wait, what conditions?&quot;.
He has this phrased like it's the ability to decide which laws you follow, and that it's an ability being withheld from the general public (although I seriously doubt that at least the former is the case). This is yet another false claim made by "freemen" or those who claim "common law defences". Notice of Understanding has no legal meaning unless the context demands that it evidences a meeting of the minds for the purposes of contract formation. It is a well-settled principle of common law that in order to be bound by a contract, there must be an agreement. Put simply, I cannot bind someone simply by sending them a Notice unless it is a right conferred on me by some earlier statute or legislation, or legally binding agreement. I tried searching for a solid definition, but all I could find was people/organization's Notice of Understanding and Intent and Claim of Rights. The reason you've found nothing official about the terms Notice of Understanding and Intent and Claim of Rights is that there is nothing official or legal about those terms. They are ordinary terms with ordinary meaning being bastardised by deluded people who believe they can fine the government and refuse to be bound by the law of the land. Of course, none of this holds up. What is the purpose of declaring your Notice of Understanding and Intent and Claim of Rights? It might make you feel better, even though it has no legal, practical or other effect.
The USPS and other postal services have created a service called Digital Postmarks or EPCM (Electronic Postal Certification Mark) to address exactly this problem. Basically you can upload any document that you want to be "unalterable and time stamped". The service computes a hash (a number that will change if the contents change), and store the time stamp and the hash on a secure server. If, at some time in the future, you want to confirm the authenticity of the document, you can upload another copy - the fact that it produces the same hash proves it's not been tampered with.
There is no special rule that says that a resignation has to be handwritten. Handwriting is important in very limited circumstances, such as wills. For example, if you write your will by hand and sign it, it is known as a 'holographic' will and no further formalities are required (depending on the jurisdiction). In contrast, if you type and sign your will, you must have the will also signed by one or more witnesses (again depending on the jurisdiction). If you tender your resignation by typewritten letter, and the employer demands a handwritten letter, and you refuse, then you have still resigned. The only time the employer has to agree to your resignation is in the case of a fixed-term contract. In the case of ordinary employment, you can resign at any time (by giving notice); this is a unilateral act. The employer's demand for a handwritten resignation letter is probably motivated by tactical considerations such as a concern that you may later claim to have been fired and they made you sign a form letter to get out of paying your severance pay. But it is not a legal requirement.
Every state requires at least two witnesses to a will unless it is entirely written in your own handwriting. A lawyer as a witness is fine. A spouse as a witness is not ideal as she would be an interested party if there was a dispute over whether it was executed. It may not be prohibited, but I would never do that in my practice ever. I discontinued a will signing just last week because we only had a lawyer and a spouse and not other witnesses. I would be somewhat concerned.