Pilots in the US have a lot of freedom. I can fly pretty much anywhere and land at pretty much any public airport without asking permission or even telling anyone. If air traffic control is involved it's generally to help me avoid other airplanes, not to tell me where I can't go. There are some general rules for safety (at least 1000 feet over cities, for instance), and some restricted areas and special rules over places like Washington DC. But pilots are basically free to go where we want. Temporary Flight Restrictions. Most of these are one day restrictions for specific events. The blue dot in the Gulf of Mexico is because of the oil spill: only Coast Guard below 4000 feet. The red dots around Iowa are for Obama's visit: can't get within 30nm of his stops. The little dot in Dallas is for George W. Bush, just 1nm under 1500 feet where it's probably not a good idea to be flying anyway. Most of the TFRs are safety or security related and seem reasonable, although it's rough on business when Obama is vacationing in Hawaii.
Then there's the weird ones. There's been a "temporary" flight restriction over Disneyland since 2003. Why? The 3nm buffer doesn't provide meaningful security; the cynical theory is it stops banner towing. There's also a blanket TFR for sporting events: no flying over large stadiums during baseball, football, Nascar, etc. I don't want to be the jackass buzzing the big game. But it's pretty difficult to know where every stadium is (not all charted) and know the schedule of all major sporting events in the area.
Pilots have a pretty good deal in the US, I'm prefectly happy to have some limits for everyone's safety, security, and comfort. I just hope we don't keep expanding the restrictions to make a complex mess that pilots can't understand.