It could be the case if the people did not bypass the rules for the post count.I have in the past made use of contests to help generate traffic but something I have learned when offering contests to help with traffic, especially with forums is how easily it can affect your site when there is no interaction and just members there to try and win the contest.
I wouldn't ever be against running contests in the future but I would always be cautious.
It's a very good way to drive traffic to a forum. It's why new website owners always make use of it to bring in more people in their forum. I'm currently in a forum contest where the winners will get $40, $20 and $10.Do you make use of contests to generate traffic to your web projects? How effective was it in your case?
This is another way to look at it. If eventually that those contests stops, believe me that people will leave but the only people that can stick back will be the ones that have already made some great impacts in the community not minding if they get the wins or not.This eventually proves to be counter productive at the end of the day. How often can you keep up with the contests? What if you eventually stop, will the people still be around?