Although I've personally never shot at a POB weapons platform, and have never participated in any base sieges except on the defending side, I'd be interested to know where and when it has been said or signaled by the admins that disabling them was considered a rule violation. It's not listed in the exploits in the rules, as far as I could see. It was was always my impression that it was known and tolerated by the admins, in the discussions I saw.