The rules are pretty clear for those who understand.
As per EA, servers are not allowed to restrict the use of weapons, by restrict it means not allowing players to choose certain weapons by modifying game code as done by severs for games such as CS etc. Therefore you cannot run a public server that only allows you to choose a knife or does not allow you to choose a M320 in our config. The rule does not state that you are not allowed to warn, kick or ban people after they have used a weapon, ie throwing a nade or using an M320. The rule is pretty obvious as the a huge amount of top 100 servers are metro only and kick you for using explosives. As long you are not meddling with their code, they cant care less about what you do on a server.
Hope that clears the cloud about the rule.