The premise of Once Upon a Time is that all of the characters are from fairy tales. This works pretty well for the principals, but begins to break down when extended to necessary random extras. To illustrate, the Valentine's Day episode has the principal women from the show out at a bar and there are a ton of extras enjoying themselves in the background. In other instances there have been construction workers, hospital patients, etc.
Is there an explanation as to which fairytale characters these extras represent? Since everyone in Storybrooke is from a fantasy world, are we to assume these extras are random townspeople from the fairy tale world?