There is one name chip that does car derived business that doesn't advertise the fact here that I could most certainly name, possibly 2, and more than likely plenty of others. The key point seems to be that certain individuals DO trade outside of pf but because they don't publicise the facts here they are seen to be getting away with it.
No one wants to open up the huge can of worms that is going to get opened up if some of these names gets mentioned, so I won't mention them, but you could probably name 3 of them if I gave you 3 guesses.