All contests, whether hosted by WFP or user generated, will have a predetermined prize pool and number of entrants. Any contest labeled as “Guaranteed” will always run and pay out regardless if the contest starts unfilled.
Some structured contests, however, require a specified number of participants. If that number of participants is not reached before the start of the contest, the contest will not take place and your entrance fee will be refunded. For example, a head to head contest cannot take place without 2 willing competitors and a 10-person contest will not be conducted with only 9 users.
Once a Fill to play contest is filled, users will not be able to cancel their entry.