Yeah, I can see how that could help. Am I understanding correctly that you would require a deposit that is subject to forfeiture if caught cheating? But in that case, wouldn't there be a dilemma between pricing it too high for those who need it most and pricing it too low to deter cheating?
Maybe another piece of the puzzle that would help with my worry about hiring someone to participate would be ensuring that any participants are fully aware of the value of their proof of uniqueness.