Only the once, but in rather an odd way!
I was driving back from the centre of London in my old green mini. (This was about 18 odd years ago) The clutch stopped working altogether!
Now, I can quite happily drive a car without a clutch- especially an old mini! But getting into first was a bit of a problem as I had a non-driving passenger.
So what I had to do when confronted with a complete stop, was jump out, push the car up to a speed I could get it into first and then away! I hadn't done bad- made it all the way to Putney before I got stopped. The one and only time I've been pulled by a bike cop. (Although I've had many dealings since)
He ignored the fact my tax had run out, was so impressed by my ability to go up and down gears (he'd been following!) Then directed me to a parts shop not 50 yards from where he'd stopped me, where I got a slave cylinder which he then fitted for me at the side of the road
I wish I could extend my thanks to him now.
So in my experience, bike cop good, you can guess the rest!