What might make it dangerous is a shorted 317. Don't know if the sender can survive the heavier (~.1 to > 1 amps) current that would result. For example worst case:
14.4 volts, 317 shorted Vin to adj, sender at 13 ohms: > 1 amp best case: 317 shorted Vin to Vout, 14.4 volts, sender at 100: .096 amps. The above is purely a guess at what Fred might have in mind.Ed