I was a tour guide at the National Air and Space Museum for a dozen years. I still remember seeing the exhibit plans the curators had, which called for a then 90-year old airplane (a Curtiss JN-4) to be mounted such that people could look down over it from the balcony. All of us docents who saw that immediately said "what about the kids who will drop pennies onto that precious canvas and wood thing to break it?"

Six months after the exhibit opening the Jenny was removed from that location, never to be returned to that exhibit. Because sometimes museum guests aren't just pushing things too hard, they are actively taking steps to destroy things, just to see if they can get away with it.