I have only seen that happen once. 99% of the time, the emitter junction on the pass transistor fails, opening the circuit and no charge occurs. If it did stick on, just unplug the regulator connector or either field wire and limp home.
I fished an old black with yellow lettering regulator and a Kmart/Penske ignition module out of the trunk extension area where I kept them in case of a failure on the road. Been there for 28 years undisturbed and forgotten.