I asked Steve House comment on this since he had a first experience with GR recently in Canada. Let's see what he says...
Even though Canada may be different from Bolivia, Switzerland or Pakistan ....
I friend of mine a few weeks ago injured his foot while climbing in the Swiss alps. He was able to walk back to the hut but he could not descend from the hut to the valley.
He contacted GR but things were a bit complicated (I do not have more details). Eventually he waited a day in the hut and eventually somebody helped him to get down. In Switzerland the charge you 2800 Francs for a rescue...
I am curious about this issue because I climb a lot in the Alps in Frace, Italy and Switzerland and soon I will be planning a climbing trip to Patagonia...I am member of the AAC and of the Italian Alpine Club, the membership this last one would pay for any rescue in the Alps.