Visible crew/equipment: In many of the racing scenes the camera crew's shadows can be seen at the bottom of the screen. (Corrected in the DVD version).
Visible crew/equipment: After the Firebird crashes after racing from the cops, the Wraith turns around. As it does, the crew and equipment are reflected on the panels of the car.
Answer: After the first race where Augie is killed the sheriff says "I've been waiting to catch you guys in the act. Been waiting and watching." So we can assume there were complaints made however the sheriff may not have had enough evidence to shut them down completly. As far as the state police, I'm not sure. May be a jurisdictional thing.
Mister Ed
I agree with this answer. Packard was very careful not to flagrantly break any laws. He even said this to Loomis in the "paper doll" scene later in the movie - Packard says that the gang hadn't done anything except "bust the speed limit."