You're shooting yourself in the foot by saying this. The more people there is on a game, the more likely there will be hackers/cheaters. Same thing with Windows/Linux/Mac. See the point ?
If the explanation is about hackers allowed to spoof the GUID, then BattlEye have failed. No system is foolproof (same for other anticheats I guess)
BattlEye still needs to be improved on this point..BE can permanently or temporarily ban players from your server. The advantage over ArmA 2's PID banning is that the BE GUID cannot be hacked/changed client-side, therefore the only way for a player to get unbanned is to buy a new game/cd-key.