There is an asymmetry in your reasoning that I don't doubt is in many court decisions due to sovereign immunity, but need not be universal. If the law is declared unconstitutional, then that law was unconstitutional the whole time. Therefore there was no legal basis for the people-who-happened-to-be-employed-by-the-government to do what they did. And I'm pretty sure the laws against false imprisonment and extortion weren't passed yesterday.
Sorry, but that's insane. You can't legitmizime criminalizing and imprisoning someone for the the crime of not having a time machine. You can legitimize the government making amends for its mistakes.
You do not need a time machine to look at the law as it stands, judge that the legality of an action is unclear, and then prudently choose to not do it. As I said, this is the dynamic everyone who is not a government employee has to deal with, and it encourages a dynamic of staying well away from the edge of the law.
Err, what? The constitution is itself part of the law. If a legislative law is ruled unconstitutional, then that legislative law is invalid, and always was. Ergo there was no authority to perform the searches they did.
You seem to be implying a different model under which unconstitutional legislative laws would remain in effect, but the people who passed them would be personally responsible for having gone against the constitution.
The point is to make government agents afraid from testing the borders of the law. Regular citizens don't get any breaks either if their scheme was later ruled unlawful by a court.
