Man, even I'm not curmudgeonly enough to want a kid's ice cream stand shut down (I am definitely curmudgingly enough to complain about kids, but I still let them live their lives--it's my problem that I don't like how loud they are.)
Is it possible that someone might get sick from it? Yes. But when it comes to a kid's ice cream or lemonade stand, it should be up to the people whether or not they want to take that infinitismal risk.
There always has to be someone out there trying to ruin everyone else's good time. People need to mind their own business.