Disney is a special one off...
Disney had repeatedly lobbied congress and the FAA to place Disneyland and Disney World within a restricted area. After all, as Kritchlow said, Disney want's their parks to be immersive and they cant control banner towers and sky writers who might advertise a competitor hotel, park or other activity nor did they like the noise and traffic congestion of the non-commercial & commercial overflights and sight-seeing tours.
For years they were repeatedly shot down. The closest they got was in 1998 when they opened Animal Kingdom. They requested again a restriction over the park and the FAA granted a "wild-life noise-sensitive area" which requested but did not require pilots to remain at least 2,000 ft AGL above the area.
In the wake of 9/11, the FAA implemented a number of TFR's including the one over Disney. At the time they were intended to be temporary but Disney decided to change tactics. Instead of trying to get a restricted or prohibited exclusion for Disney, they managed to get exactly what they wanted all while appearing to be in the interest of "National Security" and not once mentioning "Disney" by name by having congress force the FAA to maintain the perpetual upkeep of the existing TFR placed over the park in response to 9/11.
Buried in a 450 page appropriations bill proposed in July 2003 and signed in January 2004, (Public Law 108-199) is the following section:
Section 521(a) IN GENERAL. -- The Secretary of Transportation --
1) shall, without regard to any fiscal year limitation, maintain in full force and effect the restrictions imposed under Federal Aviation Administration Notices to Airmen FDC 3/2122, FDC 3/2123 and FDC 2/0199; and
2) May not grant any waiver or exemptions from such restrictions, except --
A) as authorized by air traffic control for operational or safety purposes;
B ) with respect to an event, stadium, or other venue --
i) for operational purposes;
ii) for the transport of team members, officials of the governing body, and immediate family memers and guests of such team members and officials to and from such event, stadium or venue;
iii) in the case of a sporting event, for the transport of equipment or parts to and from such sporting event;
iv) to permit a broadcast rights holder to provide broadcast coverage of such event, stadium or venue;
and
v) for the safety and security purposes related to such event stadium or venue; and
C) to allow the operation of an aircraf in restricted airspace to the extent necessary to arrive at or depart from an airport using standard air traffic control procedures.
So basically, Congress mandated that the FAA perpetually enforce several post-9/11 "security notams/TFRs" specifically 2/0199 covering high-occupancy events (aka those annoying pop up notams that show up with very limited notice anytime some event draws a crowd) and 3/2122 & 3/2123 covering Disneyworld and Disneyland.
From my research, the FAA doesn't seem to like these TFR's anymore than the pilots... They're a pain to determine if an event will require the TFR, its painful to keep controllers, FSS stations and most importantly pilot aware of the notam given its nature and there is also an incomplete plotting of all facilities large enough to have the required occupancy.
As such, it is possible that despite a pilot doing everything they are supposed to do in a pre-flight obtaining all relevant information, they can land and find out they busted the event TFR because they flew over a stadium that had an unannounced event.
The law also killed an entire cottage industry of banner flyers, sky writers and sight-seeing tours in Orlando; less so in Anaheim.
AOPA is lobbying to have them killed but the TFR is/was temporary and it cannot simply be removed or changed to a restricted/prohibited area by the FAA as congress would still ultimately have to approve the removal of the TFR.
The FDC notams have been superseded by new notams but the new notams refer back to the originals under which the TFR was established. It should be noted that at the same time the sporting event and Disney TFR's were initially created, other TFR notams went out such as 3/2127 which established an ADIZ around NYC and 3/2290 which restricted VFR overflight of Chicago and which allowed Mayor Richard M. Daley to bulldoze Meigs Field in the middle of the night.
