Thinking about races that would've ended differently this season if these 'rules' had been in effect earlier.
Canada - Vettel wins, obviously. Not only does he not get a penalty, but he's still got options if Hamilton gets close again.
Hungary- Verstappen wins (he only had to hold Hamilton off for four laps, easy to do with these new rules).
Monaco - Verstappen doesn't get a penalty for driving into Bottas in the pitlane so finishes 2nd.
France - Ricciardo forces Norris off and overtakes Kimi offtrack, but they are both first-time offences so he keeps both positions.
Britain - Does Vettel get a Black-and-White flag for hitting Verstappen rather than a penalty (it wasn't dangerous, just hard, manly racing)?
I'm sure there are more, but it's late.