Dirty number plates

[r3loaded]

This has been bugging me for a while now - I've noticed quite a few cars around recently (primarily BMWs and Audis, unsurprisingly) which are otherwise clean except for the number plates which are often caked in a thick layer of dirt and dust.

Could anyone shed any light on why this is the case? Do the owners do it deliberately in the belief that the number won't show up on a speed camera or something?

 

[r3loaded]

It particularly does my head in how obviously localized the dirt is - spotless lights and bonnet, but filthy plates.

I've got a good mind to attack these cars when I see them with a bucket and sponge.

 

[r3loaded]

Another hit and run post from a troll poster.

Possibly

Anyway, to re-iterate my point, I'm not talking about the drivers covering hundreds of miles in winter everyday - they have an excuse since the whole car ends up covered in muck. I'm talking about the ones who deliberately avoid cleaning their license plates while the rest of the car is spotless, even in summer.