For your first point (and I only know this from accidental experience), it is extremely easy to bypass emissions equipment on a car, 1995 or newer.
On cars from 1995 an up all cars had to have an OBDII compatible port that lets car manufacturers read out the codes, but it was primarily designed to speed up emissions testing. Instead of putting the car on the tread mill now all they have to do is plug in the computer and get the codes back from the car. The car is continuously monitoring its output anyway to get the right fuel/air mixture to get the best possible gas mileage.
The way it does this is with a series of O2 sensors that are placed near the exhaust port on the engine and continuing down the exhaust for one or two more.
The thing is that if one of those sensors is faulty or dirty it will return that code, however since cars also have to run when the sensor has broken or just isn't installed the computer will completely ignore it and not fire a code for it at all. On my car all of my O2 sensors were broken, and I didn't know it until I brought it into a mechanic as I didn't think it was running correctly. I had passed emissions since my computer said everything was fine, but if it had been put on the tread mill (which would have cost me the same $27.50, so the state makes the same money whether they computer it or run it) it would have had "high" emissions because the fuel/air mixture was not right and I was basically dumping unburnt fuel into my exhaust.
After the O2 sensors were fixed my car ran much better.
It surprised me that my car didn't throw a code for the O2 sensors being completely gone as far as the computer was concerned, but it just goes to show that some things are easy to bypass.