I'm all for self-service repair, but how would calibration be handled? If a repaired iPhone were somehow slightly out of spec, it is unlikely anyone will be hu

I'm all for self-service repair, but how would calibration be handled? If a repaired iPhone were somehow slightly out of spec, it is unlikely anyone will be hurt (sure, it isn't impossible). What if a repaired ventilator, insulin pump, etc is out of spec, though?