My memories of rescue/recovery insurance in the 1960-70s through British Mountaineering Council was its main purpose was to cover the cost of professional guides, if a helicopter was bought in the guides association for that area included it in the cost of the whole. As far as I know, there would be no voluntary participation.
Have things changed, then it was assumed that the professional guides associations in France would sting British Climbers as a matter of course because they were less likely to use their services, professions that rely on providing services for tourism have to mitigate some of their charges in the cause of good public relations.
In this country, rescue has been a free service because it started off from being provided by fellow mountaineers, I doubt a volunteer would be given a place on a stretcher today, whereas in the early sixties I was put on the front end of two stretcher recoveries, the minute I arrived on the scene. When RAF mountain rescue teams contributed it was described as practice for the real thing, should they go into action?
Back in the Alps I recall nearing the summit of the Dent Du Requien, I traversed out on the bottom edge of a slab that overhung the main face, obscuring part of the Snowfield at the bottom of the Aiguille, just before I started to climb the fracture line in the centre of the slab, I looked between my legs and a helicopter appeared there neatly fitting between my knees before it disappeared under the edge of the rock I was about to climb. Was it carrying supplies to the Requien Refuge or was it flying off a casualty? Never did find out, cynical old age gives me a third option, some 'too rich' braggart got flown in to avoid the day-long slog up the Mer de Glace so, he can build up a CV to get on an Everest attempt.
After thought, the heli did have red marking so perhaps it could have been a resue.