Sometimes the restrictions are very tight, like when we latch on to another contest (one page dungeon contest for example) but usually the voters are the ones who judge the worthiness of your entry. Lots of folks will vote for whatever they like best regardless of how well it fulfills the requirements. Others will not vote for a piece that ignores the premise. I don't think I've ever seen a host disqualify anyone except when the qualifications were necessary, like the example above.