It's been an hour, and a very clear trend is emerging: http://www.wolframalpha.com/input/?i=bar+graph+13%2C+5%2C+10... Is there any reason why 4x more people would be banned within four days of a payout than any other part of the cycle? (This presupposes the poll results can be trusted, which seems dubious at best. But if this survey is trustworthy, then I wonder what it implies.)
I think it's also worth noting that it can be trivial to get an account banned if you just get a few people to keep clicking the same ads all day. So 'legitimate' bans could happen even when there was no foul play from the person showing the ads.