First off, winching is the last option. If there is no other way of getting them out, winch.
Secondly if you have to winch, make it as low as you can, and if you do ALWAYS have a tag line and someone on the end of it who knows whats expected of them.
Never ever do a stretcher winch without a tag line.
I've seen quite a few similar videos from the US that don't seem to follow any of these guidelines.