I remember one Derby football match when parking on double yellows was still being enforced by traffic wardens and police alike. A council van with three traffic wardens parked up on the double yellows gave me a wave as if to say watch this. They then proceeded to dish out approx 30 tickets to the offending vehicles. Yes you guessed it, out came my ticket book and stuck one on their vehicle. The traffic warden returned and was not best happy to find the £30 FPN on the screen. At least these got off with a warning.