They weren't already doing that?

I agree that understanding this up front as a platform owner and making it clear to everyone else saves misunderstanding, angst and embarrassment in the long run, but I think well meaning people are conditioned to be a little more accommodating than they should be and sometimes shy away from the responsibility of making their own judgements (which could be wrong!) by hiding behind a thick rulebook, leaving them open to bad actors willing to game the system. Make the judgement call and as a consequence be judged by the community and it will all find balance.