Wording is by the suggestion interpretable
It seems the wording of the rules is miss interpretable and if this is the case then I would suggest they are poorly written I'm afraid.
Having read though the main shoot rules I think there are areas still open to abuse other than the kneeling definition.
d. The surface of the pad on which the stock rests must be flat and not shaped to provide lateral support to the stock.
Now in my reading here (off subject sorry but to make a point), those nice sand bags often used on hamsters when not full, hard and flat are ILLEGAL based on the above rule.
It's difficult to write every single detail into an instruction, I know from experience of writing detailed engineer guides.
The trick is to as they say keep it simple stupid :-) and cross the t's and dot the I's
Just my thoughts
Steyr LG110 FT, Sightron SIIISS 10-50x60 LRIRMH