Should't a court decide on this?
As many have commented above, there is a conflict here between the rights of the owner of the phone to continue using it, and the right to life etc. of those around that user. Whatever your perception is of those relative risks, there is undoubtedly a conflict, and the normal procedure for resolving such a conflict is to ask a court to issue an order before undertaking the action.
Even if the order is unopposed (as it would probably be here), the responsibility would be transferred to the court, freeing Samsung of liability, and it would reduce the "slippery-slope" issues, by involving a 3rd party arbiter. Yes, there are issues of which country(s) to do this in, but that's what corporate lawyers are there to resolve!