I think it means that of all users who merit the post, top 5 who send the most merits will be accepted into the campaign. I don't know what the real intent was but it does sound like a trade. More so than e.g. the other debacle about the soccer contest where someone offered merits as a reward.
What a sucker! If only he knew that he was a few merit away from joining the cycling club, and becoming a part of the all-powerful, awesome gang.