Many, if not most, National shows now require that you get permission from the pattern designer to enter and must give credit. Small variations made to a pattern don't suddenly make it your own original design, like changing the borders or replacing two HST with a flying goose unit.
Another problem I have with shows is not requiring a mention if the quilt was professionally longarmed by another. Some shows do but I know of plenty of entries into some of the biggies, like Houston or Paducah where the entrant made no mention of it even though I knew the person who longarmed it was not the same person as the maker. Some shows don't have it on the entry form unless maker and longarmer enter as a team.