Lessons from A Craft Show

Leaving the house to be a vendor in my second craft show, I thought that the worst that could happen was that I would not make the entrance fee in sales. Lesson learned: Lots worse than that can happen: teenagers running through your area and breaking a lot of your work, people coming to help and getting hurt, and not making the entrance fee. Another vendor told me (afterwards) to not put anything breakable near the edges of the tables, or near the front or back of the tables. Good advice, but for me not practical since all of my work is glass. I'm thinking of surrounding the tables with barbed wire, but wonder if that may be off-putting to buyers?