I was under the impression that airlines/TSA can't anyway mark your luggage even if it contains firearms. Some airlines give you a tag, but you are suppose to p

I was under the impression that airlines/TSA can't anyway mark your luggage even if it contains firearms. Some airlines give you a tag, but you are suppose to put that inside your luggage, but I might be wrong about this or my info might be very old. I'm basing most of my stuff on this video https://www.youtube.com/watch?v=KfqtYfaILHw https://www.youtube.com/watch?v=KfqtYfaILHw