So what about, making different penalty?
He've all seen how much time reparing stuff costs and such. And i think we can well agree upon SHIFT + P to be a drivers mistake. So it could be good ebough to make a SHIFT + P penalty something like 2 laps penalty or even 3, while DC still costs a team 1 lap.
But in this case you would most probably end up with same unsportsmanship as in last race. But it would hurt also, so it would make them think 2 times before doing it. Just penalise everybody harder, and we will see more mature racing imo.