I'm not interested in discussing this any further, I'm just saying that if they get "too good" with users who "misuse" their products, then their system gets abused, like you say. It's a kind of education if you will, they can't "spoil" their customers.
The person didn't do it purposefully of course, she just bought crap batteries, and apparently they overheated. That's it.
Yes, not everything is black or white, but there are some problems that come down to a binary choice (like spam messages for example), and even if you say otherwise, these are black/white problems that have to be solved.
With a more specific case of course there are details, but overall you can come out with the choice of "say it's our fault" or "it's not our fault". And that's what people understand, because we all try to simplify the data we perceive.