I don't think you should ever take anything too seriously, and in a case like this where you can't take it too seriously, you don't have to worry too seriously about the should, because the can't doesn't allow for any other option :)
seriously though (but not too seriously), what's wrong with having a fun contest with prizes and having people who may or may not be perfect judges to judge it? The prize will only carry as much importance as you attach to it I think.