My dad, who is a Florida resident, will be joining us for one day during our next visit to WDW. From my research, I found that he can get a 1 day ticket at a 10% discount if bought in advance. What does that mean? Where does he buy it in advance? Can I buy the ticket for him at the hotel and then he shows his proof of residency at gate or does he have to be with me to buy the ticket? Thanks