Getting Banned in Custom Games

So I attempt to play Halo 5 on campus and have had to deal with lag spikes on many occasions. To find out if I have lag after that, I set-up custom games to test my connection before joining games with other people so I don't screw up other people by being disconnected. What I have found out is that while I am testing the connection in a custom game, if I leave the game enough times, I get a BanHammer. What I would like to understand is how can I be banned from Halo by leaving a game I created and I was the only one playing in?