Alright, let's take a step back and look at a non-extreme scenario. I understand the point everyone is making about liability and I don't want to discuss/argue that point. There is a good thread titled Liability in the Backcountry Health & Safety forum.

This scenario involves two solo hikers, one east bound (Joe) and one west bound (Tom).
(No, this isn't your junior high math problem)
Remember the points of check, call, care and see what we can learn.

It is about 3pm on day 2 of a 5 day hike for Tom and he comes upon Joe sitting on the side of the trail and appears to be in pain.

Tom - Howdy, how ya doing?
Joe - Not so good. I tripped and think I sprained my ankle pretty good.
Tom - oh man, that's a bummer. I've had some basic first aid training. You want me to take a look at it?
Joe - sure, should I take my boot off?
Tom - no, leave it on. It will help control the swelling. Do you have a sit pad or a sleeping pad to sit on? It might make you a little more comfortable. We can prop your foot up on your pack to help elevate it and slow the swelling. You got any water?
Joe - yeah, I got about half a liter.
Tom - when was the last time you drank anything?
Joe - about 10 minutes ago.
Tom - how far back was the last water source.
Joe - about 2 hours.
Tom - hmm, mine was about an hour ago. I've got a half liter and a full 1 liter platy.
Joe - I've got an empty platy in my pack.
Tom - you got any first aid supplies.
Joe - yeah, I got a few things in my pack.
Tom - are you taking any medication or have a history of heart disease or diabetes?
Joe - no heart disease or diabetes but I do take blood pressure medicine.
Tom - you look like your about 35, am I close?
Joe - no, more like 45.
Tom - well, let me feel your ankle and see if we can see how far up the swelling goes.
Joe - dang, that hurts.
Tom - yeah, the swelling goes about half-way up your calf and it's about one and half times bigger than your other ankle. Looks pretty serious. How long ago did this happen?
Joe - about 20 minutes.
Tom - well Joe, you got a few choices here. It's two days to the nearest trail head. Did you leave a hike plan with someone? When are you expected out?
Joe - I left a plan with my wife and I'm supposed to be at the trail head in two days and call no later than three.
Tom - There's about two hours of good daylight left. I can find a campsite near-by and set up camp and help you get into your tent. We can also figure out a way to wrap your ankle to give it some support. We can see how you're doing in the morning and if you want to try and walk out. Or, you can stay here and I can go back to the trail head and get some professional help. It'll take me two days and then drive to town or at least some place I can get a cell phone signal. Do you have enough food for 3 days?
Joe - yep.
Tom - you got any ibuprofen?
Joe - yeah, I'll take a couple of those.

So, using the Check, Call, Care protocol - what do we know.
Joe's got a pretty bad sprain. He's 45 years old and takes blood pressure meds (it would be good to know what kind and dosage). He's running low on water but appears to be hydrated. He's not in shock and is coherent. We're two days from the trail head and he has enough food. Water is a concern.

If Joe decides to hike out in the morning, I'll go for water and make sure he has both containers full. I'd show him how to wrap his ankle using a couple of bandanas or perhaps some straps from his pack. I'll use his gear rather than mine.
If he can't wak out, I'll decide if I'll hike back to the trail head and call/go for help. Or, if I'll continue on and try to find a signal or a road and flag someone down. Someone may be coming up the trail behind Joe and they could continue on to the trail head and call/go for help. We need to get his contact information of who to call.

What we learn from Wilderness First Aid training is how to improvise and use the gear you have (or better yet, what the victim has).

You can also "suggest" ways they can treat themselves.

Without getting into the discussion about liability, what else could/should we determine?

Tango61