I think the main problem is when something hard hits the glass on the screen. I agree that normal “drops” are usually no-damage affairs.
However, the physical damage that can be done by a two-to-ten year old to an iPad pales in comparison to what internet-related damage can be caused....:0)
It's also bad news if it lands squarely on the corner -- that focuses all the impact on a very small area. A lot of broken screens, probably most of them, have the telltale cracking radiating out from the corner.