1. You are mostly right, but in genuine US style, the other events surrounding the convention have sort of grown to become larger than the convention itself. It

1. You are mostly right, but in genuine US style, the other events surrounding the convention have sort of grown to become larger than the convention itself. It's likely they were selling these at some kind of event or area not directly affiliated with the convention. 2. I'm sure this is the case, but they were likely able to circumvent this rule by not selling in an area directly controlled by the convention. 3. You don't need some kind of license for selling most goods, but food is basically a controlled substance. If it's pre-packaged, the packager is regulated, not the retailer. 4. Non-perishable food is regulated mostly at the packaging & handling level. EDIT: They could have also claimed that it was art and not for consumption, which is a way to skirt the labeling requirements.