As a judge I would not usually take the crowd's reaction into account - most often, people cheer for things that happen to be popular at the time (whether the costumes/presentations are good or not), or for gratuitous fanservice...and I've seen far too many halloween contests where the most popular costume got the prize (usually a cute kid or a half-naked woman) instead of the good costumes.
That said, however, I do recall one instance at Toronto Trek a few years back where an entry got a special "audience appreciation" award because their presentation had been so funny and entertaining that the audience had demanded an encore. That's a rare occurrence, though.
COSTUME-CON 32 - 2014
the den of sarcasm - my website
Magpie Creations - jewellery and wa-loli accessories
The International Costuming Convention is coming to Toronto Canada!
4 Days! 4 Masquerades! Dealers, Tours, Parties, Costuming Panels and Classes, Cosplay, Props, Doll Show & Competitions, Steampunk, Sci-fi, Fantasy, and so much more!