Side one: if the AED will not allow you to shock except when it will make things better, then anyone could have one and use them at will.
Side two: Slippery slope leading inexorably to getting beyond one's knowledge and certification.
If the machines were perfect we wouldn't need techs or doctors.
PS: Unless they changed the laws here in Calif, responding to a scanner or scanner app carried in your car is illegal.
SF fire has an app that alerts nearby citizens of arrests so they can beat them there