I used to always pass on car park tickets, but the car-parks here are pay on exit now, the cameras put your car reg into the system on entry, so you need that to pay before leaving.
On street parking are still 'pay & display', no car reg required, but I only use them for very brief stops, so tend to just pay for 20 minutes, so bugger all time left on them, to make it worthwhile to pass on.