Howdy,
The basketball rule was once strictly enforced until the ROC clarified that shuffling to a more stable stance without changing shooting location would be permitted. Generally it's quite obvious if a shooter is trying to improve their view of target after the firearm is loaded & cocked ready to fire. The shuffling seems to happen more with shotgun, although some newer shooters seem to shuffle with every gun.
So, how do you coach a shooter who's taken a stance in a bad shooting position with a cocked & loaded firearm in hand(s)?