I don't think you're in the minority. I don't wanna sound like I'm full of vinegar, but the rules state "No costumes". I'm cool with outfits that are themed, or teeter the line of costume - but full-on costume should not be allowed. I saw a couple of dead cheerleaders at the event, and the last thing Universal needs is them to cause trouble and another guest to assume they're related to HHN.