I have once, just finished a 19hour shift, was on call and up at 4am for an emergency recovery job from the police.
Pull up, spoke to the officer had a laugh and he went home to bed I finished off the recovery and spent the day at work.
Was driving home that evening, saw a clear stretch of road and put my foot down, much have been doing 65 or so in a 50. Went past a police car and thought "oh dear" he pulled a U-turn, caught up with me and pulled me.
Low and behold it was the same officer from the 4am job, he asked me what I was doing and said that I wanted to get home as I was shattered and he then asked if I had been to bed yet, to which I said no I worked all day.
Think he felt sorry for me and he has been in bed through the day, gave me a telling off and said "for someone who picks up cars that have crashed like this morning, you of all people should know better"
He let me go but preceeded to follow me the 10miles almost to my door step. Not sure if this was out of concern because I was dog tired or to make sure I got his point.
Either way he was a gent and was well within his rights to ticket me, and if he did I don't think I would have contested it, I was over the speed limit and bang to rights.
Sometimes a ticking off is the better way to deal with the situation.