When I worked for Disney, the "The" was always contentious. I trained the Cast Members at the Disney Reservations Center. One thing we always emphasized was the use of proper nomenclature. Even if it was annoying, Cast Members always were to use the full official name of everything.
When I joined the company, I was told that the official name of the park was "Magic Kingdom". So when I started training, that's what I taught. However, some of my colleagues insisted that the "The" was part of the name, too.
(I still operate in the mindset that I must use the full name of everything. You'll never see an abbreviation in any of my posts on here. And when I write about resorts, I always use the full name. Although, I'll probably leave off "at Disney's Wilderness Lodge" when discussing Copper Creek Villas and Cabins.)