I don't have numbers for you, but the answer is likely of the order "almost always after a rollover". The cage will protect the occupants from being crushed, not the high-tolerance door and hinge clearances. And rollovers are common.

Again, the confirmation of priors effect is extremely strong here. People are leaping from "Tesla manual door handles are difficult to open from inside the cabin" to "All Tesla accidents are the fault of the interior door handles".

Of course you can very often open doors after a rollover, maybe it's very different in US cars but here we have complete stress and collision tests, and if doors can't be opened after a rollover, your car won't pass and won't be sold on the European market (unless you get an exemption for collection/luxury vehicles, but Tesla won't qualify).

Citation? I've never heard of such a test. The opposite is routinely tested: making sure doors don't pop open (and potentially eject occupants) during rollovers. Demanding the very tightly engineered door mechanisms to survive that kind of stress and remain operable with mere handles simply isn't feasible. Even in Europe.