The mesh pattern of even the smallest deniers of ripstop is too large compared to whatever the strap is made of though. The grid squares on the strap are only 3-4mm across at a maximum.
Here's another picture of the strap, this time of the join between the 2 halves and the webbing strap that runs across the back of the shoulders:
It's quite clear from this picture that there is some kind of rubber or foam involved as the stitching is compressing it. You can also see the back side of the strap and it's a smooth matt fabric, just like the bonded polyester lining you get on neoprene. It's quite frustrating as I'm sure I've seen that texture on the back of neoprene but can't remember where!
