I doubt that you will see any lake water in the Disney area be used for sports that involve people actually getting into the water. It's not just the amoebas, but the bacteria alone is murder to control, then there are always our friends, the 'gators to contend with.
"If it's a body of water and it's in Florida, there WILL be a 'gator in it."
Then of course, there are our LOVELY friends the water moccasins. (Cottonmouths to go by another name).