While the hospital and Disney might not have held national press conferences about this, it would have gotten around. How many people per car in Space Mountain? 6 right? (Sorry, I'm a frequent Lander and I get the two SM confused.) So there were 5 other people in the cars, and 2.5 of them probably would have ran off and told their family, and the wildfire would have began. The DisBoards would have heard about it before it reached Frontierland on the rumorphone.