I agree. You have no idea whether a ticket is valid until you get to either a Disney resort or Theme Park. For the last year or so, tickets have been linked to a biometric scan of the owners fingers. If someone else used them first, then you are screwed. A DIS'er reported being in line behind someone trying to use ebay tickets with his family. They were turned away at the ticket turnstile and had to buy full price passes if they wanted in to the Magic Kingdom that day. It was said that the kids were mortified, and thier dad was very embarrassed.