What happens if somebody confronts you?
3) A police officer: If they tell you to stop photographing, you have to do so.
Incorrect.
Edit: actually no, this was correct as originally written. Second guessed myself.
I don't know if it's true federally, but it's at least usually a lawful order for a police officer to order you to freeze / stop moving for purposes such as ensuring maximum officer safety, which could thus include taking pictures in
some circumstances.
And although in the absence of any special events or circumstances it PROBABLY wouldn't normally be a "lawful order" to say to stop photographing on, for instance, the sidewalk, it can be very ambiguous whether various orders are lawful or not, since they can make claims about being threatened by your gear, or they may have legitimate external reasons to be emptying the street that you don't know about, or who knows what. For all you know there's a sniper on a roof that has a vendetta against people whose photos are being taken, and they're eliminating potential targets by telling you to stop.
And in some states, it very well may be illegal to just not follow a direct order, period (unless theyre telling you to stab a guy or something. But ceasing an action like photography is clearly not itself committing another additional crime or anything).
There's also common law considerations, even if nothing exists in a statute in your state regarding this. For example, if your photography is obviously disturbing the peace via loud arguments, etc., a police officer may well be within his right to force you to stop.
It's all very gray, and state dependent, etc. etc. which overall makes it a terrible idea at best to not follow such an order, and at worst it could hold up in court as illegal not to, depending on what the situation actually was.
Edit: Nor is this exactly a very pressing "civil rights" issue that we all need to be standing up for, in my opinion. Police officers can already just detain you entirely, legally, if they feel it necessary, so it's not a big deal for them to be able to tell you to do things that constitute, essentially, just partial detentions, like stopping photography, because this doesn't lead to any runaway power scenarios since they already have more power than that.
When it comes to SEARCHES, it's a different story (your memory card), and I do suggest strenuously standing up for your rights in that regard, by clearly and politely saying "I do not consent to a search" and then simply not complying, if asked to see photos (but don't physically resist if they go for them anyway).