I do two craft shows a year. I can tell a fellow scroller in a second. The first thing they always say is " nice work. What saw do you have?". I know we all check out what is selling that day in other booths. The two shows I do are inside and there is a sign at the door,"cameras allowed.
If a show won't do what it can to protect your work maybe you should find another show to sell at or at least tell the person what is going on.
Carlton