Antitoxis i'm not sure if it's a rule but i think i have seen or seen someone banned for this reason.
Battlereport 1 : http://battlelog.battlefield.c…6849752482432/1763144517/
Battlereport 2 : http://battlelog.battlefield.c…5527310279296/1763144517/
At 0:13 you can see only 29 players at server.
As you can see at battlechat i told to him flying rules and he said that he know rules, but he pilots the heli anyway.
And 1 round later he do again with 31 players as you can see at 0:06.