I think that most people know that little kids are disgusting and covered in germs and viruses. People buy the lemonade because they want to support the kid, not because of the quality of the beverage.
Last summer I noticed several of the lemonade stands in my neighborhood had bottles of hand sanitizer and that the kids were actually using it. Maybe there is some level of awareness out there.
At least little kids will usually wash their hands because their parents tell them to. High school cheerleaders with no oversight are a different story.