I've had my licence for 11 months.
(Red P's)
Been pulled over 10 times. Never fined. Never been done for speeding/burnouts etc.
Always a "random" breath test. I've had to lift my bonnet 8 times.
Never been asked to rev the car, or anything like that. The cops physically look for a front mount, turbo, blow off valve etc.
I have been asked a few times if my oil breather is a blow off valve, and once if my pod filter (which is enclosed) is a blow off "thingy".
Cops have gotta do a job, and when they see that red P plate they will definately do it.