Originally Posted by fastball
Inside the engine, there are sensors which constantly sample the oil...
I doubt it. It probably counts engine revs, cold starts, warm starts, & whatever sensors already exist. That's a lot more reliable than counting miles alone, but it's still not perfect.
If you put some garbage oil in there, it can't actually tell that it's worn out early. OTOH, if you use Mobil-1, Amsoil, or whatever, it also can't give you credit for using a better oil.