The problem is people shitpost for a lot of reasons. Some are promoting off forum sites by linking to it in their shitpost, some do so just to read how great they are, some because they think this is facebook. We have seen action when things are bad enough this year with campaigns and participants receiving temp bans, I think that sent a decent message out to most as we've seen people be more cautious about signing up blindly.

It doesn't matter the monetary limit you impose to someone it could be a couple weeks salary so they would gladly fill as many spots with alts and turn out garbage all week. If you want to make a difference, go around reporting posts, if their quality is poor it will result in them not being paid and losing the incentive.

Account sales suck, but not much can be done. People are willing to sell entire packages of personal documents for cash. So I don't think there is any reasonable level of precautions the forum could take to prevent someone from trading in accounts. At least now there is a good hacked recovery system to prevent hacked account sales as best can be done.