You are seriously positing that car manufacturers would install decoy sims in their vehicles to discourage people from finding the true sim, all so they might collect data without potential user disruption?
Given that, I hardly think that 'decoy sims' are much of a stretch.
Okay, nobody is putting in a placebo sim, but in software, we DO have placebo controls. If you flip a switch saying "don't track me", that usually means "track me slightly less". If you delete something, that doesn't mean delete it - that means keep it, but say it's deleted.
If you go through the Windows install, for instance, even if you flip off all the stuff it will tell you "we're still going to do this, just in less circumstances".
What are those circumstances? I don't know. I'm not even sure Microsoft knows.
It is everyone's information that they value, not that one guy who goes to the trouble of killing the radio.