[sadawi]

What you're buying isn't a vote, but a receipt. What if we could increase the supply of valid receipts enough to make them effectively worthless?

For example, voting machines could drop duplicate receipts into a bucket that voters are free to rummage around in.

[lmm]

How would you tell the difference between a valid and invalid receipt when the voter came to verify it?

[shinratdr]

Or just not have receipts and avoid the issue altogether.

[sadawi]

Sure, but there's a benefit to receipts: you can verify that your vote was counted correctly.

[shinratdr]

Well, you can verify that the receipt says your vote was counted correctly. That assumes you both trust the receipt system and believe that whatever tampering was done to cause your Obama vote to become a Romney vote couldn't have possibly also resulted in the receipt providing incorrect information as well.

[sadawi]

Ideally, I think the complete list of votes (with receipt confirmation numbers, but no names, obviously) would be available for inspection.