We can debate if it actually happens or not and not get anywhere... I'm addressing the *legal* questions.
Inside the borders it is *illegal* to do what you suggest, where outside our borders a US citizen would not be afforded the same protections and some of what you suggest *might* be legal activity. Inside our borders the assumption is people are US citizens/Non combatants and have constitutional rights to due process. Outside our borders the assumptions may be different depending on the situation, so they may assume you are a combatant/non-Citizen and are thus subject to the rules of war.