I believe that a game must have some governing control, the forum needs a little bit of regulation and control or as sauid the site rules would go out the window and then members would be breaking the rules. However on the same note we rely on DMs to manage this within a game or for a user to report the abuses. The only person I ever had to bann however was someone who could not grasp the scope of what the rules allowed them. It happened to be a game I had joined to see where all the problems stemmed from as well as to play with some friends, to that end, this member had reported daily problems with players not respecting them, we had long discussions in private forums about them because her claims kept coming and they were empty. Upon joining the game I began to realize the problem was not the players, who were respectable members of the site and friends, it was the DM. In this case the DM had taken the rules to so much an extreme she was breaking more then one, she had formed this image in her mind that a DM is a tyrant and that site rules don't govern her, she was all powerful, that even moderators and administrators were under her in her forum.
It was quite a intense moment for me, as I had never gotten so into it with a member and in the end it ended up with her banning because it was there constant disrespect and inability to comprehend the simple rules that all site members are equal aside from admins and mods who have the powers to keep the peace, not horde it over people.
So while a game needs to at least follow the rules of the site, and while we give DMs mostly free reign over there forums, we do not under any circumstances allow them to freely break the rules of this site. No member DM or player has the right to disrespect another player. Not really on topic, but it goes to enforce the point that respect means a lot, when your a tyrant no one likes you, and when you don't stand up for the protections alloted to you by the rules you might get walked over, Bottom line know your rules so issues like the one above can be avoided.