Another nice post, Jerry, although I am not sure about your willingness to carry someone else's pack. I've repacked my own pack to carry more of the load, but taking another hiker's pack? Wow. I think I would choose to sit down with them and talk them through the problem. Sounds like low blood sugar (give them a snack) dehydration ( give them water) or just plain need a rest (give them one).

But then, I've never had someone in a group decide that he or she simply can't hike any more...

Maybe you all started too fast to begin with?