They look nice, but they can be turned on the C17 (and probably other military airplanes).
Commercial airplanes have safeguards against in-flight thrust reverser deployment. That is why they only work in tandem with the ground sensing systems - like the airplane must firmly believe both main landing gears to be physically on the ground for both reversers to be operational.
This is a rather odd comparison. You can slam the brakes, yank the steering week, and do all sorts of things to intentionally make the car crash.