Prevent cheeting on polls
 

I'm running a truck of the month contest and using vB's poll system for voting.

One member who wasn't doing all that well went to a bunch of other boards and asked peeps to come over, register and vote for his truck.

I think this is very unfair, though policeing it with the current system would be very difficult and time consuming.

Is there a way to prevent new users from voting? For example perhaps they would have to be members for 90 days or 25 posts.

Has anyone done a hack like this before?

Put new users in a seperate usergroup.

Use promotions to only allow them to vote after X days and X posts.

Doddle.