Driving without a number plate is asking to be pulled over. Whether they're traffic or not Police cars are pretty common in Northampton. Doubt other large towns/cities are that different.

Same goes for 'smoked' plates. They might just fool the camera but if the recorded speed is over the limit then an eyeball is brought into play.

Eyeballs + brains are not so easily fooled and there's a chance that illegal plate will be added to the charge sheet.

Another dodge I recall if you had a reg that includes an "F" or a "P" or a "3" for example you turned those letters into a "E" or a "B" or an "8" with a felt tip marker black or whiteboard dry-wipe pen.

And it's done quite a lot over here in France!

Something else that is recently surfacing is a legal maneuver to get around the deduction of points (it's the other way around over here). You pay a legal firm a fee and they guarantee that you don't get the points deducted - it works 100% if the photograph of the offence does not identify the driver. You still have to pay the fine though, after all that's the whole point of the exercise isn't it?

https://easy-rad.org/