I think the main thing that has changed since I was young is that strangers are now very reluctant to confront youths who are misbehaving. Yes, there are some parents who would object, but I suspect that most would be quite happy for their child to be reprimanded if doing wrong. Unfortunately the press have blown up those cases where it has gone wrong to the level that many adults are now frightened to confront a misbehaving child. Also, when I was young, my parents knew virtually everybody in our road, which reduced the chances of any confrontation - and also me and my siblings knew if we did anything wrong, it would soon get back to our parents. If a child is not challenged about small transgressions, they will inevitably progress to worse things.
Insurance can never make up for the many man-hours time devoted to building a model. Even with an off-the-shelf model, it may not be possible to replace it if that particular model is no longer being produced. Valuing such things can be very difficult.
I am surprised that they didn't have overnight security, but I suspect that if it were only their own layouts they might not have thought it worth it. Or perhaps the venue has their own security arrangements. I suspect that some venues might not accept people sleeping overnight in them, although this probably just needs some tactful wording about what the "security guard" is going to be doing.
One thing that I have been unable to discover from the press reports is if there were any visiting layouts or exhibits affected? It is one thing to have your own stuff trashed, it is far worse if you feel partly responsible for someone else's stuff being trashed.
