I have a friend who was suspected
of card counting at a certain casino, he then won a VIP BJ tournament and was backed off from blackjack on his very next trip. I think if you win a VIP tournament and you are already on the fence with Mgmt regarding your skills, the tournament win might be enough to push you over the edge to a backoff. He wasn't sorry, as his tournament win was a lot of extra EV that he didn't have to play tons of hours to get.
Other than that, since counting is not part of tournament play I don't see how playing in a tournament can hurt you unless you're already about toast at that casino to begin with.