The daily price changes are only a barrier to pre-booking IF the price fluctuations are based on anything other than "weekends and holidays cost more." I don't think they will be based on anything other than that, though, because that seems to be what they landed on for the ILL charges and is the simplest solution for them. So if they know that Christmas week is going to be $22 instead of $15, then they could easily collect your $22 per person per day in advance (just like they're doing on the other coast despite their new variable pricing model). It would be a nice benefit for resort guests to be able to book even just 1 ride per day ahead of their stay, but they obviously don't want to do that and have their reasons for it (be it the cost of updating the system to allow it, the desire to control behavior while in the parks, or just because they know they don't have to because people are buying it regardless).