I do not own a Tesla, but I have ridden in one without knowing this. This is not the fault of the passengers. This feature should be obvious to anybody in the vehicle, not something you have to rtfm for.
Well the burning passengers definitely got it in their rear doors as a result of a market focussed design. And by that I mean he charges as much as the market will take and cost as little as possible with as few safety constraints in the design and in the factory as possible.