This new rule will cause great discomfort to the "larger" shooter and will very much disadvantage them.
Why not let good sense prevail and set a maximum size for shooting seats and let people have support to the shin/ankle.
If people kneel across the narrow end of the bag with the main portion away from the body that will stop any suggestion of "sitting"
PS, I am able to conform the new rule but not without discomfort.
I wonder if people will develop ankle injuries and subsequently claim for that injury.
Less is more.
More or less.