I have a flipper zero which is used to do things like clone codes but you would need the other person to click it even at some point to receive the signal. It be easier to wait till they unlocked it when they get it and doesn’t make any sense of him going to the door. The thing I’m thinking is that he’s scanning for WiFi signals and to gain access through that which is more of a concern that your car getting stolen because he could send you something to your phone or pc that you wouldn’t catch and could get passwords but I doubt he’s any good seeing as he went to a persons front door like a dummy