Don't people on this very board talk about how they can "spend all day in Diagon"? Hyperbole or not, people do like to just sit there and soak it in. Once the newness wears off and people have been a few times, I agree it won't be a big problem. At first though, knowing they are limiting access and that it'll be massively crowded for the foreseeable future, a percentage of people will want to spend a bunch of time there. Especially in DL where its a high percentage of locals who have seen everything else in the parks plenty of times. Not to mention, the people getting hotel rooms and getting the reservations specifically for this land aren't your tourist family who are going to see everything in the parks and have to keep moving. People are going to want to stay past the "get out" time.