How do you actually implement the VIP reward on your kickstarter?

I don't believe there's anything internal in kickstarter that facilitates this, so it looks like people usually just handle this in a makeshift way? Anybody done this before either as a buyer or seller and know how to do it?

From what I can tell, you make a "VIP Reward" that is the VIP price, and tell VIP's to buy that one and then later confirm they are VIP's by comparing to the e-mails they used for their reservation.

BUT - how do you stop other people from buying that tier? If it looks better priced than the others, wouldn't other people just try to book that reward and slip in under the radar? Then after the campaign, you're left to clean up the mess of charging those folks the difference.