Years ago, when I was working at a university, our department moved into a new 'modern' building - in the offices, instead of book cases, we found very long shelves lying on clips that anchored into wall strips - we were assured that these shelves were strong enough to hold books - so I loaded my library onto the shelves, being careful to balance the weight along each shelf. Then, with a slow grinding noise, the wall strips pulled away from the wall - the idiotic contractor installation crew had neglected to fasten the strips to the wall studs, and didn't even use any type of wall anchor - just used long screws ....
