Was it like that little girl whose iPod caught fire and Apple asked her to sign a NDA?! That request backfired hugely and caused a PR problem!
All we know that someone _claimed_ that an iPod caught fire and _claimed_ that Apple asked them to sign an NDA. Now assuming that Apple didn't feel that anything happened that they were responsible for, and that they at most would have paid her for being quiet, not for any actual damage, asking for an NDA would be the sensible thing to do. I heard of the PR problem; I didn't hear of her getting any money out of it, so you can draw your own conclusions.
And the strange thing is that things like iPods catching fire, exploding screens, cars that accelerate suddenly and cannot be stopped, these things always come in waves and then nothing. So it seems to me that this is not actually anything wrong with the products, but with people.