I think that the FA in question proved herself to be right in her assesment of the passenger. How can you give her flack for that? You can argue all day about why YOU wouldn't have been able to pick out the right person to tell. She obviously was good enough to get it right.

I think that my point is valid regardless of whether she should have told anyone in the first place. Once she chose to tell a passenger, the part of choosing the right person she obviously got right.