Well there are already 'rules' and always for this place just like any site registered or hosted in the us. Not too sure what the aversion you have to "guidelines to what is considered spam" is but it is reminiscent of a rebellious teen.
But if we look back into the case of TK banning WW2 then we could clearly see there was a discrepancy between claims and it was very hard to get anything straight, on the other hand if there were bannable - guidelines for what is considered spam I would think it would be a lot clearer both to people viewing(the ban) it and to people posting.