Cool. What about the people they come into contact with who are generally staying home, but have to go out to necessary places like grocery stores, pharmacies, gas stations, etc.? They didn't "decide on their own" to be around someone who went to a huge gathering, it happened by chance.
Amusement parks cannot safely or sanely open and please its guests fully until we've reached herd immunity or a proven vaccine is developed. Both are a long way off. Full stop.