In reply to Neil Williams:
> .. just in case a row or two of stitches is designed to rip at a low force.
Nobody would design a shock absorber to do that because there's only room for a finite amount of stitched sling, and that would be a row or two of stitches effectively wasted because they'd rip without doing anything useful in a fall.
The trade-off for the designer is to have the shock absorber deploy at a high enough force to be sure your fall will have been arrested before it runs out of extension (at which point it has effectively just turned into a big static sling), but also at a low enough force that it doesn't hurt you (much).