My biggest fear at a show is that someone would walk off with a model, or that an unattended kid would be found on the floor with one of my models trying to make the wheels move. LOL! If I take a model to a show, I don't put the responsibility of looking out for the model on anyone else. I sit near it and answer questions about it, but keeping my eye on it as long as I can . . . luckily, nothings ever happened to any of my work.
You have to respect others' property in order to get that respect back.