I can't see that the ankle roll breaks any present rule.
As I see it the future vote will be whether to insist upon the roll hence not allow bags.
Presently on option allowed is to use the beanbag to bridge between foot and behind the knee (the knee must contact the ground). This is the support offered by an ankle roll without the suspicious bits that stick out the sides.
If you use an ankle roll that can compress to 4 inches then that's the definition required for the bean bag.