I agree with both mlm and chip on this. Sitouts are a real pain and there is little that forum operators can do about it. I find these people that do this constantly just to get ranking points despicable and even worse than the all inners and trash talkers.
To these people and I use that word reluctantly I say learn some manners and have respect for other players. We know who you are and we recognize you for the greedy slimeballs that you are.