They're trying to litigate or legislate spontaneity out of our lives with all this "no singing" stuff. Most game shows these days are owned by foreign companies based in countries where people are generally don't do things on the "spur of the moment." (I read a book on European customs and manners and found out that the Dutch are generally not spontaneous.)
Thank God there's one show that's still American-owned, and that is "It's Academic". I'm enclosing some YouTube clips where former host Mac McGarry breaks out into song spontaneously: