Ah, but you just wait until these concepts evolve into practical consumer products. Then you'll see Grandpa zipping along in units with sensors that keep him from bumping into things, and GPS systems that make it possible for him to get where he's going even with poor eyesight. Why, those units will even have monitors to make sure the return Grandpa home if he forgets where he is.
How will you know if he dies?
Shalom.