One thing about this forum is people can have different opinions and we never seem to get around to fighting.

We all at least say we plan and leave itineraries. Most of them could probably be improved. In the past, we have had separate threads on this which were very good.

Unfortunately, we don't have a big volume of knowledge of how people screw up as it seems the reports are kept confidential.

To keep in line with what I believe the OP's intent is, I'll present the following scenario. Falling in a fast moving stream.

If I had the opportunity to teach this, say to a group of scouts, I'd have them take a swimming test in a pool or lake and see how fast they could swim. Then I'd take them out to a fast moving stream and toss a stick in to see how fast the water is moving. It's most likely, they will be at the mercy of the water. From this they should learn not to walk across logs over a fast moving stream. Often there is a slow area not far away.

In a fast moving area, I'd try to float with my feet downstream. If it was feasible, I could make a simple life jacket out of my shirt or pants.

The second half I really have no great idea. If I fell in, I'd try to pick an angle to slow water where I could stand up. I might teach rescue techniques such as reaching with a long stick or tying a stick to the end of a rope and throwing it past the swimmer so they can catch the rope. Going into the water for a rescue often a bad idea which results in two fatalities.

Depending on the temperature of the water, I might teach getting the person stripped down after rescue and inside a sleeping bag. Then make some coffee (coffee is always my solution) to help them warm up.

If I really wanted to learn this scenario, I'd go white water rafting where they teach survival techniques before you go out. Most of them actually have you get in the water.

Going back to prevention as I ramble in my mind. It's possible to get in trouble in about 8 inches of water. It's easy to have your legs swept out from under you and hit your head on a rock. The prevention is twofold. First of all water often looks shallower and slower than it appears. Tossing something in the water to see how quickly it is flowing is a good safety measure. Crossing facing upstream and using your poles for balance can make it safer. You can safely feel with the poles before stepping to see if there is a quick drop off in the bottom. If things start to get uncomfortable, go back the way you came.

Feel free to pick my thoughts apart. That's how I learn