I gotta agree with Jarhead here...
That cop has a job to do, and while that job may occasionally cause some inconvenience or expense to you, that job also involves protecting you and the people you care about.
Say you flash your lights to warn that oncoming car of a cop ahead. He slows down, passes the cop, then speeds back up and hits a pedestrian a mile down the road because of his .09 blood alcohol content. What if that pedestrian was your wife, son, mother, or best friend?
Suddenly it doesnt sound like such a good idea, does it?
Same goes for ramp checks. People may be getting on that pencil-whiped 421 on the ramp. People with very little aviation knowledge who trust that they will be flown in a safely maintained aircraft with a well trained and conscientious pilot. If their assumption is correct then a ramp check is a non-event.
If you dont want a ticket, slow down. That simple.