You then have to think why the gas valve was sticking in the first place. The common cause is oil( known as 'heavy ends) in the pipework from the gas cylinder which may also be in the regulator. The regulator may also start to malfunction. I know it sounds contradictory as oil normally is a lubricant , but the forces required to open and close the gas valve are small and oil jams up the valve stem , it also can cause the rubber valve seat to swell, which is what causes regulators to jam up(closed) . Attached is a photo of an 18 month old bulkhead regulator which failed due to oil build up ( it was in a motorhome) . The gas bottle was one of the refillable types and I can only assume the filters at the filling station were not doing their job , The client has opted for having an oil filter fitted. Overfilling a gas bottle is also a source of liquid being injected into the regulator and pipework along with oil , also causing freezing of the regulator and pigtail as the liquid boils off with a limited surface area.