Bill, I would expect most charging problems to be "operator error".. but with Li-polys the chance for a catastrophic result isn't emphasized sufficiently.
These are not batteries for a less than rigorous approach, they can and do cause extensive damage when -abused-.
Like any substance with this potential, the problems should be known to the user.
Then it's the user's fault when he does it wrong.
A friend that works on military UAVs says Li-polys when tested in combat conditions demonstrate an "explosive" response to bullets..
I've vented a few ni-cads but no Ni-mhs.. yet.
I charge everything outside on the concrete patio, just to be safe.