I assumed the motivation was rednecks with tires outside the wheel wells spitting crap all over other cars and the road. However, I do not know.
Here is the law anyway:
http://www.pabulletin.com/secure/dat...3-48/2265.html
Agree with TRY...M3 - most places would not say anything. I'm going to take my car to a different garage for the mechanical inspection.