Sorry to hear this about those kids. One of the solutions to the problem of a customer dumping the puzzle out and then not putting it back together and then leaving was to shrink wrap them. I live up in cold country so I put heat shrink plastic on the inside of my windows and come spring I take it down and rather than throw it out I save a good portion of it for shrink wrapping the puzzles. You wrap the puzzle as you wish it to be seen and tape the edges together on the backside. Then using a hair dryer on low pass it over the plastic and it will shrink and make a good protective glove over the puzzle. The customer can pick it up and look at it but you do not have to worry about them not being able to put it back together. Some shows are like that, keep the faith and have fun.
DW