What I find to be most interesting about this is that it is quite obvious that they actually have no authority to do anything to him. If they could have done anything, you can be quite sure they would have. IOW, the entire exercise is a complete bluff.
No, they didn’t really have the authority to do anything to him because he was coming off his flight. However, if he was flying out, they sure had the authority to keep him from getting on the plane.
I don’t know how you could win in that situation.