Kit was always going to go high tech as people competed to gain that extra advantage.
A lot of stocks do look very deep forward of the pistol grip. There is a pic of me in there and my stock looks very very deep. Lots of people question me about it and it's been measured a few times. It's actually 140mm from centre bore so looks can be deceiving.
The kneeling shot you mention is of Tenchy who shot a superb 59 on day 1. He will know the rules inside out and I'm sure he will ensure his hand will fall forward of the knee. Photos can be deceiving and Steph probably used a tele lens for that shot which can shorten depth which may give the impression, from that angle, that the hand is closer to the knee than it actually is.
It's very very difficult for marshalls to police everything like ... is that hand actually just forward of the knee if it was dropped down ... is there anything forward of the butt touching the floor. As far as I know a hamster resting on a gloved front hand that is on the ground is fine anyway. Most has to be left to the honesty and knowledge of the shooters.
Steph ... quality pics as always. Many thanks for sharing them.