Earlier quoted context omitted.
Mark reportedly lives in California, a two-party state. Wouldn’t he be running afoul of wiretapping laws, regardless if he’s recording criminals?
How does Amazon and Google get away with it? When you put their listening devices in your home, do you sign a legally binding contract? Honest question, I've never bought one. If a contract is sufficient, does it have to be signed in writing or witnessed? If not, then could he have a sign at his door stating that acquiring the package provides consent to monitoring? Is there a lawyer here that could answer those ques…
One of the first rules of the legal system is that you don't get to violate the law. This INCLUDES the situation where someone else violates the law first.
In many places this principle is repeated. For instance, you DO NOT get to bump someone's car if they run a red light for instance.
(and no, EVEN the situation where you literally had no choice still isn't an excuse. There is only the small "non-exception" that earlier laws can override later laws. For instance, keeping someone safe takes precedence over obeying traffic lights. If you can avoid an accident by running a red light you MUST do so. There is an explicitly defined order in which laws can override one another, even though I would strongly agree that it's not exactly a clear thing)
So the thief (or whoever) can sue this person for things like willful damage to property, violation of privacy, ... and that the package was stolen won't be a valid defense.