I've run across an interesting problem with this sort of thing.
I was recently explicitly encouraged to enter *in competition* by a masquerade director at a small con, even after explaining that I won best in class previously and just wanted to walk the stage and show off. They didn't have a division system, and I ended up participating in their "fan favorite", applause-ranked competition instead. It felt kind of weird and arrogant to insist that I was too good for their competition, but I just couldn't honorably enter that size of show with that particular costume.
Has anyone else had that happen? What do you do when a con doesn't have an out-of-competition option?