The number of places are limited to win, therefore it is uncertain to win something there, I try my best to be part of winners but due to offline commitments this doesn't happens for several participations, it depends on your free time and availibility too that is not the same for all members.
But it is reverse for someone having a job. He may post in the pause of launch or early before working hours office or after work and during working hours on office, others will post more and earn more, that lets chances between members aren't equal even in contests.