I don't care who brought them there, prison guards have no business working in public, they are not trained to do so, have no idea what legal protections ordinary citizens have, and refuse to identify themselves in violation of laws all other agents of the Federal government have to follow (though some might flaunt that too).
I wonder if they are exempt from punishment or oversight if they screw up (which I presume will happen).
There's no need to wonder: yes they are exempt from punishment and oversight.
It doesn't matter what laws they break because it's pretty clear that the executive branch has no intent of abiding by any laws; they won't do so unless forced and clearly no one has the power to force them to do so.
I have no idea how this will end, but I'm fairly sure it won't involve justice for the people.
I wonder if they are exempt from punishment or oversight if they screw up (which I presume will happen).