Man, I now know how to easily keep kids out of exploring urban ruins... get a "Halloween Sounds" CD, stick it into a player on repeat, put it somewhere in the building where it will echo just enough to sound like the place is haunted.

I'll bet it works better than any alarm or security guard alive.

Except that you're wrong -- Motts has visited several places that are in fact getting renovated and/or restored. Yes, in most of these cases the abandoned places are destroyed, but in some they are saved... thus your initial premise is faulty.