Not a lawyer, but a lifetime as a potential target of such suits. Very briefly, 42 USC Section 1983 speaks of "under color of any statute, ordinance, regulation, custom, or usage, of any State or Territory or the District of Columbia, subjects, or causes to be subjected, any citizen of the United States or other person within the jurisdiction thereof to the deprivation of any rights, privileges, or immunities secured by the Constitution and laws." It's very broad language that takes in most government operations, except judicial actions.
It can take a careful review of hundreds of cases to guess the outcome of any particular potential suit. But it basically means that a lawsuit can address a situation in which a government action done in the course of official conduct goes beyond what is reasonable and necessary to carry out the legitimate mission and that violates a protected right. In what we've been talking about, it might, for instance, involve a violation of the right to be free from unlawful search and seizure. The issue might turn on whether the government action was specifically authorized by law or was within more generally reasonable governmental acts and the extent of the violation of rights. There are also provisions in most state laws, both criminal and civil, to address this, but 1983 is a common way to go. A great many 1983 suits never come to anything. And the situations are very often not very clear-cut. So long as the action is reasonable and necessary to what we expect police to do, the courts are very careful not to stifle appropriate police conduct. You see a lot of opinions with language like, "This is exactly why we have police."
Larry: It would be entirely reasonable to call on local hams who had appropriate DF equipment as what they used in foxhunts. It's not something local law enforcement maintains. It would probably come to that if it went on long enough and the agency efforts failed.