I think this is the most ignored rule:
[url=https://cfldb.ca/rulebook/fouls-and-penalties/major-fouls/#r7s2a4][/url] [url=https://cfldb.ca/rulebook/fouls-and-penalties/major-fouls/#r7s2a4][/url] [b]Article 4 — Unnecessary Roughness[/b] A player shall be penalized for any act of unnecessary roughness against an opponent, including but not limited to:
(a) Piling by a player who, in an unnecessarily rough manner, falls upon the ball carrier after the play has been terminated. Any player in possession of the ball, who falls to the ground without contact and is not attempting to advance the ball, may only be touched down and may not be contacted in any other manner
I’ll bet it happens on every other play. Ball carrier is stopped, and a defender comes flying in to apply a hit after the guy is on the ground - as though the incremental half-inch of forward progress is a matter of life and death.