You usually design so that a single point of failure can't hurt you. If one position sensor (they use pots, since they're practically indestructable and not vulnerable to ESD, power transients, etc) fails, you sense the problem with the other sensor. They're not "primary and backup", they're both equally important.
You postulate that both sensors short out at the exact same instant, since any other scenario would power down the vehicle. They did it within milliseconds of each other, and they did it at some intermediate, yet believable level. (They didn't "peg at maximum", as that would also alert the software there was a problem. Instead they pegged, identically, at some believable value.
You postulate that both sensors short out at the exact same instant, since any other scenario would power down the vehicle. They did it within milliseconds of each other, and they did it at some intermediate, yet believable level. (They didn't "peg at maximum", as that would also alert the software there was a problem. Instead they pegged, identically, at some believable value.
I'll take the other side of that bet any day.