Could US mayors/governors order their state police to arrest unmarked federal agents? Could the local US governors/mayors, who reject federal agents on their streets, legally order their local police force to arrest all people, who are violence and don't wear any insignia? Or would it be illegal for them to arrest the federal agents, even when they don't wear any insignia showing their role as federal agents?
Revised for clarity in light of comments State and local police can arrest anyone who they have probable cause to believe is breaking state or local law. Like all LEOs, Federal LEOs can break some state and local laws while enforcing Federal law. When they grab someone off the street and hold them in a cell, they are detaining them, not kidnapping them, and so on. However, to avoid arrest, the Feds have to identify themselves. That's because state and local LEO who know they are dealing with Feds on federal business no longer have probable cause to believe a crime is being committed. State and local police can arrest Federal LEOs who they: a) have probable cause to believe are breaking state or local; and, b) have no reason to believe are Feds enforcing Federal law. In other words: Any Fed who refuses to identify herself to a local LEO can be arrested if there is probable cause. State and local police cannot, however, arrest Federal LEOs just because they are not wearing insignias. That is because: a) there are no federal statutes requiring federal LEOs to identify themselves; b) the Supremacy Clause says federal law takes precedence over state and local law that conflict with it; c) at least in Portland, the feds were not operating under any sort of formal agreement with Portland or Oregon officials that required them to have identification. While it is hard to prove a negative, the question of whether Federal LEOs are required to identify themselves has been looked at recently by reputable sources. They all agree there is no such law. For example, the answer from Lawfare: Broadly speaking, law enforcement officers do not have a legal duty to disclose either their identities or their agencies of affiliation, even if asked directly. Certain municipalities require police officers to identify themselves if asked, but there is currently no federal statute requiring officer disclosure of such information. The article points out that the two main types of cases involving police identifying themselves really don't apply: police who are working undercover, notably in sting operations, and police searching and seizing property. They go on to point out: Separate from the question of federal law, several states have adopted laws and regulations requiring law enforcement to identify themselves. For example, under New York City’s Right to Know Act, a broad set of police reforms that went into effect in October 2018, officers must tell civilians at the start of some interactions “their name, rank, command, and shield number.” (Also, many departments have policies that generally require officers to identify themselves, although with exceptions. You can see examples of the policies here.) Again, these local laws do not apply to Feds because of the Supremacy Clause. NOTE: As several of the news stories note, the lack of identification will make it very hard to hold Federal LEOs accountable for their actions. Accountability requires identity.
In general, yes, police could do this. I am not aware of any US state or locality which requires an officer to execute a stop as soon as a traffic violation is observed. Whether the police would act in such a way is another question, but in some areas maximizing citation revenue is a high priority, so police in such areas might act in such a way. If police think a person's actions are &quot;suspicious&quot; and think that the person might be involved in some crime more serious than a traffic violation, it would be common procedure to follow without making a stop or arrest to get a better idea of what the person was doing. Many police I have encountered seem seriously concerned to stop someone driving in what they consider an unsafe way as quickly as possible, and so stop violators promptly, but I don't say that motivates all police all the time.
It's called police and prosecutorial discretion to discern when to arrest and prosecute; and that situation in particular is also the result of a decision of the jury of the court of public opinion. Permits are required to sell on the street in Oakland. But not everyone who sells has a permit, and not everyone who is confronted about not having a permit is arrested and prosecuted. There are simply too many potential cases to prosecute. And, the police officer has the discretion to ticket or not. When you get pulled over while driving or riding a bike, you don't always get a ticket, since the officer has the option of discretion. When the officer responded and found an eight year-old selling water, he obviously was aware of the fact that it was a violation. But he was also aware of the court of public opinion. What is it going to look like if he arrests an eight year old and their parent? Allison Ettel was right, in a purely legal sense, to make the report. And technically, the child (and adult) needed a permit. And could have been ticketed and prosecuted. But it was Ettel was tried and convicted in the court of public opinion, and she lost her case. Happens a lot.
So my answer depends heavily on a clarification. Are the Police Suspicious or do they have a warrant? This is a big difference in the two behaviors as the former is not a thing, from a strictly legal perspective, and the police should not be harrassing Bob, who doesn't want to talk to them, when they should be making calls to get a warrant (If the police think Bob is being disorderly, they will arrest him and Bob should zip it, get an attorney down to the station, and let the Lawyer yell at the cops... and the judge... and the prosecutor and whoever else... If it's the latter case, they don't need to ask Bob to have Bob come outside... they can kick in the door and arrest Bob or remove him as part of executing the warrant. That's why you have them. In the situation as described, it reads like there was some crime in the area and the police think Bob may have some knowledge about it (he need not have done it, they could be looking for a witness). Bob does not have to say anything to the cops as per his rights against self-incrimination, so Bob tells them he does not wish to speak to them, possibly in an irksome manner and the Police won't take no for an answer. Perhaps they really think Bob might be the criminal... this doesn't necessary mean they have evidence to arrest Bob on. Perhaps Bob was identified by a guy off of security camera footage... maybe it was Bob, or maybe it was Bob's evil twin he never knew about and Bob's been home all night Keeping Up With The Kardassians (anyone knows Bob knows he can't stand going a week without knowing what Kim and Kanye are doing). Either way, it could be enough for a search warrant but just wanting to talk without a warrant, Bob can refuse and they need to respect that. Again, it's probably a bad faith arrest, but the street is not the place to have that fight... save it for the courts.
Following you around with the intent of harassing you is stalking. I don't know whether there's going to be a law actually requiring social distancing in Florida. In other states, I've seen laws set up to make it a crime to violate an order of the Director of Public Health or something like that. I don't know whether Florida actually has an order requiring social distancing by the general public.
I'm a notary. If someone showed me a marked-up license, I'd refuse to perform the notarization, and make a note of the persons name and phone number, to make sure I would never make another appointment with the person. Is there a law that says I have to refuse? I don't think so. Is there is a law that says I can refuse if I have any doubts about the person's identity? Absolutely.
Are you required to comply with a police officer's order to put your baby down in an uncertain situation and allow yourself to be handcuffed? Of course. If holding a baby could immunize people against arrest, every criminal would have a baby around whenever possible. Similarly, suppose an officer legitimately fears for his or her life or safety, or the lives or safety of others, on the basis of a suspicion that someone carrying a baby is about to produce a weapon and use it against someone. Courts, at least in the US, give wide and explicit deference to police officers in stressful situations like that, and they recognize that even if, in hindsight, it is perfectly clear that there was no danger, the officer must be allowed the leeway to act on his or her suspicions in case they are correct. The officer will of course have some obligations to ensure the welfare of the child after separation from the adult, but the only immediate recourse the adult has is to appeal to the officer directly, or perhaps the officer's supervisor if he or she is available. Any other enforcement of the officer's obligation will have to take place in the courts after the fact.
The fire department is entirely within its rights, which are the same as any other property owner. The fact that property is owned by a governmental body does not mean that members of the public can't be excluded that property. Some governmental property is public, but lots of it is private, and this would usually include most parts of fire department property. As long as you have not been denied any access to a public road by this fence, there is nothing improper about it. Anyone can walk through their parking lot, park their car there, meet friends, whatever, This is almost surely inaccurate. The fire department does not have to allow members of the public to have any access to their property and probably would demand that most of the uses you describe stop if they interfered in any way with the performance of its duties.