When you fill out the application/contract to participate as a vendor in a show, you are also more than likely signing a waiver that releases the promoter/show coordinator from any responsibility for anything that happens to you or a customer in your booth, at that show/event.
This means that if a customer cuts themselves on one of your displays or while trying on a piece of jewelry that may have a stray, sharp end, YOU are responsible!
Let us think of the lovely weather we sometimes have to deal with at outdoor shows. Your tent takes flight and on its way down the row it takes out a pottery tent and breaks/damages that artists works, YOU are responsible. An event attendee is in your booth and the heat is so bad that they faint and hit their head on your table; YOU are responsible. Ok, so now you are thinking of all of the horrible possibilities, most of which will never happen, but in today's world you need to be prepared.
I cannot give you the actual insurance company I use, but I can tell you to check with your homeowner's policy and your automobile insurance policy before you go spending a lot of extra money. If you are going to be traveling and participating in just a few or a LOT of shows in a year, there are several companies who offer 'one time' events or 'seasonal' just for folks like us.
The easiest way for you to find the insurance you would personally need (according to what and where you participate) is to perform an Internet search using the terms "vendor show, exhibit, event insurance," as there are many different types available, and this insurance does not have to cost a lot to cover you for liability.
Answer contributed by Dale "Cougar" Armstrong