Then...don't? If you were genuinely concerned, you could always ask them how they made it, and if anything seemed fishy (improper cleaning, ingredient prep, et

Then...don't? If you were genuinely concerned, you could always ask them how they made it, and if anything seemed fishy (improper cleaning, ingredient prep, etc) you can always walk away. The existence of the stall isn't in itself a hazard, and in the majority of cases, there won't be any problems at all. The problem is in the 0.1% of cases where someone didn't wash their lemons, or has been snacking on peanuts near an open container or something similar, and there's a major incident. Risk/benefit analysis suggests you should avoid it and go grab a coke instead, but there's nothing stopping you picking up a cup of lemonade and tipping it down the drain if you wanted to encourage some neighbours children to pursue their business ideas. I agree that there's less to learn, but also there's much lower risk to the children (gardening work will often involve pointy things and/or power tools), and it could well be a good place to start. I'm not sure how the licensing issue could be dealt with, since AFAIK a minor can't enter into the majority of contracts that might be necessary to obtain permits/handle licences.