It's not BattlEye, I've had it when playing with the weapons.ini file (set fireinterval to 1). Since my server refused to connect to the BE master server and I was too lazy to fetch the BE update (I only needed to test the weapons.ini) I turned off BE and it still gave the same message. However, it didn't kick me. It said I was cheating by using a disallowed weapon (I don't know the exact message anymore, sorry).
Grtz, DePhille