At SMW the public, of any kind, don't vote at all, it's all in the hands of the Judges, who are appointed by the Competition Committee IIRC.
I've had few turns at this onerous task, albeit MANY years ago, and it's no fun if you're paired with someone who's done it before. You always get overridden on a decision, on the grounds that '........I've had lots of experience......' etc. Just one reason why I tend not to 'do competitions' any more.