Both of those are good answers. It's good to have the opt-out available, as Aspiderjonny said, but it could also be a challenge draw a character in a different sub-category of that genre/style, like Euphorie said.
Even though my comic is technically fantasy, I think I will not opt out of the Fairy Tales/Medieval genre, since it is unconventional enough that I could make a medieval/fantasy version of most of its characters and still have them drastically different from their regular version.
Anyways, I won't worry about it. I'll let whatever selection process is being used make that decision.
ALSO: Is this strictly a one-character thing, or can you do two characters (or more) if your story does not have one definitively main protagonist?
My comic stars four main characters, so I'd rather draw two characters than just one. (Also it'd allow the artists to show off more of their alternate-universe style that way.)