Perhaps allow the program to check steamid when the server is empty..
(checks all steamid in the databas)
Next time the player connects, the program check if they have play before
(alredy check) if not it will do check then the server is empty (schedule time)
It may not remove the player how is cheating directly, but I can live with that
if the player nerver can play again on my servers, and you do not get lagg
Excuse my bad English