[PunchyHamster]

It's to contain the regulation into little box that controls the emission, rather than span it to entire system making it harder to repair. Then the EPA can have its "proof" the vehicle emissions are fine without compromising entire system for repairs.

[jcgrillo]

I think you're asking for something magical, like when politicians go on TV and demand safe cryptosystems with government backdoors. Any time you try to do engineering work to hinder users from using devices they own it's a really bad time. That's the purview of law enforcement, not engineering.