I drive on the street and in several years of driving with those fenders, I don't get any problems from the police. I think it's probably the rear that they worry about but I drove my previous Jeep without any rear flares at all and never got stopped. Then again I always make sure to wave at the local police and be real friendly to them all heheh.
Of course if I was suspicious looking in any way, you can bet they'd use the fenders as an excuse to pull me over.
P.S. MCE recently announced wider front fenders so if mine aren't wide enough for your state laws, I think MCE has what you need by now.