I have 13 70s, a raft of 60+ and a new group of 5 at 63 and I've only been contacted by a GM once in all that time.

<GM> (spams all 4 of my chars) Hail! Can I speak with you for a moment, please?
<me> lol...Sure. What's up?
<GM> You boxing?
<me> ayup.
<GM> OK, just checking.
<me> /salute
<GM> Have fun!

Almost verbatim what he said. They know about us, and it's easy for them to verify the legit boxers.