First question. Does the attacker have to have physical possession of either or both the laptop and the battery?

Second question. Why bother?

But then, I read something (in one of the slide shows in the links) about the guy still wanting to go on airplanes. The lightbulb finally turned on for me. This isn't about causing problems on someone else's laptop. It's about causing your own laptop battery to do bad things on command. Now this is serious. We really don't want to have an entire brand of laptops easily converted into a weapon.