This would actually be a good punishment. If you screw up, you could be forced to open source your code. If VW is serious, they could do such a thing. I guess that Mercedes wants to keep its Formula 1 code closed, but for it's normal cars it is a different case. The big car companies share so many of their technologies and even complete cars, what's keeping them?
No, it wouldn't. Want to sink you competitor?
1.) Pay a disgruntled competitor employee to deliberately sabotage part of their code base.
2.) Finger the company to the feds.
3.) Watch as competitor's IP is opened sourced (non consenting open sourced code) by feds as punishment.
Pay them to break their factory automation. Pay them to write code that randomly increases fuel consumption. Pay them to write code that only allows you to play Rick Astley songs during March.
1.) Pay a disgruntled competitor's employee to deliberately sabotage part of their product in an illegal way.
2.) Finger the company to the feds.
3.) Watch as the competitor's market position is hurt by bad thing X.
Works if X is fines, sanctions, stricter regulations, prison time for those involved, or even just a court case that costs a significant amount of money.
Thus we shouldn't punish a corporation no matter how bad it is.
As a side note, this same logic would let us conclude that punishing a person who commits a crime is a bad plan because it allows for their enemy/rival to frame them.
Reductio ad absurdum.
My guess is the motivation to force a company to disclose their source code as punishment is coming from a place of thinking that the more harsh the punishment, the more seriously actors will abide by the rules. As it's been proven to be the case in criminal law, the death penalty does nothing to dissuade homicide.
How is it different if Ford gets to see Chevy's throttle control software code today?