That's really dependant on location. I have had plenty of road trips up and down the I5 where groups of cars pass cops on the side of the road going 80, and no one slows down and the cops do nothing. Source: I'm one of those drivers.

For a minute, maybe. Foot goes back down when the cop’s out of view in the mirrors.

nah, it just gets them to slow to 20 over the limit here