MM has to be more sensitive than the other forums, as soon as an exchange of money and goods is involved - especially when the forums are sponsored by OcUK and thus bad experiences there could unfairly reflect on their business - people's expectations of the forums change.
I know that if I deal on MM I want to deal only with users who have a spotless record, I never want to run the risk of my money disappearing or having a parcel of crap goods come through the post. As soon as you start to let infractions and offences slide in the MM you'll annoy more people than you'll make happy and that is not fair in any regard.