It should always work, just like every table saw should have an anti-finger-removal sensor. Pay-per-use might make sense if the incremental cost wasn't vanishin

It should always work, just like every table saw should have an anti-finger-removal sensor. Pay-per-use might make sense if the incremental cost wasn't vanishingly small unlike, say, teams of people searching the woods or calling an ambulance helicopter. "Did not pay" or "no insurance" should never be a reason to not save a life.