I'm assuming this is a very small tournament so EA probably had no say in the matter. Just like if you wanted to go host a tournament down at a LAN cafe, there would be very little security. However, security isn't the issue here.
This guy had the gun on him, he went to the tournament with a gun meaning he was intending to shoot someone. A gun isn't a wallet, you don't need to take it with you unless you're going to use it.