Vigilantes forgo the protections of working with the State allowing them to operate without many of the restrictions that accompany civil liberties. They are outside the system; the system doesn’t work; they have rejected the system to pursue their own justice. This freedom at the expense of their quarry is highlighted by a discussion of invasion of privacy. Unlike government actors, evidence obtained by a vigilante in violation of Constitutional protections is not excluded from trial, in fact, Constitutional protections are not even implicated without a government actor.
Batman plants a tracker on your car as you make your getaway; Superman uses his x-ray vision to find stolen goods in your house; and Professor Xavier telepathically extracts your confession; if you’re a criminal Superheros are constantly invading your privacy in the name of “justice.” What’s worse is that some of the citizens who have their privacy invaded aren’t criminals they’re just caught in the crossfire. Assuming you could serve a subpoena on the Hall of Justice or the Xavier School (and actually enforce a summons) what would your remedy be for these intrusions? If you weren’t able to go after the heroes themselves would there be any legal redress in your impending court case or could you even have a case against the government?
Your course of action in these matters depends on the nature of the crime-fighter as either a government actor or a vigilante. If your captor was a government actor the invasion of your privacy may lead to the exclusion of evidence from your criminal case; if a vigilante was involved your next step is a private tort action against the hero.