I'd always unplug the battery at any static display, and still do that for work PRs. At airshows, there would usually be one or two kids, somewhere around the 8-11 y/o age that you could tell was a little more inquisitive about the switches. I'd tell them (and their parent standing there) that there was ONE switch that started everything up, but you have to find it. It was always amusing to watch the reaction....which was always followed by the parent asking, "that's not really true, is it?" or stating, "Uh oh, he/she will find it if that's true."