Hey Christopher Sounds like the Police over here mate. Slight differences: A stop by the law will usually result in being told to change the race cans and take it to a nick to prove it's road legal. Loud cans / pipes are not (currently!) an endorseable offence - no points and / or fine.
I too have seen speed cameras with paint thrown over 'em. Other vents include setting them alight and just out-and-out driving into 'em!!
We have the mobile speed cameras too. That's how I got the one and only speeding fine I have.
The funny thing is that most of the cameras face the front of the vehicle so they can snap the face of the driver too. Great for bikes - race through to set 'em off while flipping the finger
A mate does it every week to the same camera - one week there's going to ba a copper waiting down the road! He never thought of that 'til I mentioned it - he does ride a Hardley after all ....