Last year my son got stopped by 2 traffic cops in the city and with them 2 rookie cops. I just happened to be his passenger as he'd fetched me from station - good lad - and a mate was in the back. Good job I was with him though.
Norfolk plod (well, I guess all plod) have been doing that for years, I was once pulled at about 3am about 1/4 of a mile from a very rural pub car park. A friend of mine worked in the pub and we had stayed late as we knew the landlord and were chatting with him after closing time.
I was pulled as soon as I drove around the corner and as I got out of the car the copper said "Evening" and then my first name. I immediately asked how he knew my name. He said he'd just used his radio to get my car details. This was long before ANPR and unfortunately for him I knew exactly how long it took them to get the driver details and so I asked if the control room log would back him up. This rather put him on the back foot and I then challenged him as to why he had pulled me over, he said I had a light out. I asked which one and he said it had magically come back on but he was going to breathalyse me and check the car over.
At this point I asked if he knew my name as he'd gone around earlier in the evening collecting number plates and then getting drivers details early because my car was parked in the pub car park. He denied this and started getting shirty, I passed the breath test and he was now in a bit of a mood as I told him he'd had no reason to pull me over and that if he had gone around the car park to get these details he was acting unlawfully as he had no reason to pull me over without suspicion that I was up to no good. He then checked the tax disc, unfortunately it was new that day. He then also checked all the tyres which were brand new that day and was desperately trying to find something wrong with my car, he even got right into the car to nose around I'm guessing to see if we had any cannabis or drugs then as he couldn't find anything wrong he said he'd being doing a presenter for MOT and Insurance. The poor guy was fuming when I told him there was no need, I'd got the MOT done that very day and got the tax disc that afternoon so had all my docs in the car, I then politely told him that I'd be forwarding a complaint to his sergeant and he nearly lost it and started yelling at me.
I didn't pursue it in the end as it wasn't worth it but he could have actually admitted he was trying to get me for drink driving.
I also had great fun a few months later when I was with a friend was pulled for "a light out" (favourite excuse of Norfolk plod it seems) which again was an excuse to have a nosey around a car as i guess a group of late teens/early 20's in the car might be up to no good. The cop was rather upset when I noticed his car had a light out, I made a very snide remark of why he ought to get that seen to, he didn't see the funny side of that either