Jen and I were in Kansas City for a convention when Jen decided to exchange some newborn-size diapers for a larger size. Unfortunately, we'd left the receipt at home (because we don't make a habit of carrying around receipts for every bit of baby gear we take with us) and that completely flummoxed the Wal-Mart staff.
When all was said and done, I had to give them my driver's license so that we could make the 26-cent swap between two unopened, undamaged packages of baby diapers. I gritted my teeth and managed not to say anything that would get me banned from the store, although I was so tense that I signed the exchange form hard enough to shred it.
And this is why I think that I probably now officially hate shopping at Wal-Mart. We weren't trying to exchange a plasma TV or a box of donuts. We just wanted to trade up to a larger size of diapers, and this ended up requiring my driver's license and a signature.