1993; is a long time ago. Way outdated material.
Most climbers these days use a simple overhand knot. Yes a simple overhand knot with no back up just plenty of tail.
If you are rappelling one rope length it may not matter but if you have ever done multiple rappels down a cliff you know that any "mess" of extra knots is a surefire way to get them stuck when you pull them.
An overhand with a lot of tail will not come undone accidentally, you will have no trouble untying it and it is less likely to get stuck in a crack, tree etc.

For non climbers it may sound scary but it is proven ask any AMGA guide. I am sure Craig would agree.

As for rescue thing may vary but in an alpine environment the overhand is favored.