Cast members often try to see how creative they can be by making up rumors. However, although I haven't heard this indoor theme park rumor, it sounds similar to the Night Kingdom/Jungle Trek rumor from last year. With that one, people would pay up to $300 to roam about recreated parts of the world like South America and Africa and have close encounters with live animals. It was refered to as a niche park. It reportedly polled terribly with guests, something like only 1 in 8 approved of the idea. If the new rumor is true, they could be working on a new niche theme park idea, but I doubt it. Time will tell.