Just about everything.
Try this on for size, you send me some BBC code and jazz for a potential clan topic. I'm supposed to proof-read it and edit it so that it works and reads well. I send it back to you and you tell me it's trash, so in retaliation I just post the clan topic instead. Only then would you start stuff-posting in my clan topic.
You just posting in a clan topic just to prove how annoying it is is not similar to your situation.