From my experience as a yellow shirt (event guide) there, it was always MSHI or WWoHP that was bought out. The club area of CityWalk gets bought out a lot and WWoHP and the New York section of USF gets bought out quite a bit too.A lot of times IOA is bought out. The buying out of parks is a bad habit that UOR needs to fix.
It's great as an employee to get paid to do virtually nothing but wave a wand all night and give directions, but it just felt like they do it way too much. I'm fine with having the parks bought out if you do it after hours like Disney does. I just don't like it affecting the guest who paid to get a full experience and they're being cheated of that because UOR is chasing the big money.