That's the law with or without special cameras that are only there to enforce the law.
If you get caught by police instead you will also get a fine and they will seize your car as a bonus. If you get caught by those camera vans while parked they will clamp the car.
Likewise, if you are wanted you are liable to be detained the instant police recognises you. It's just that the process is very inefficient at the moment because it relies on being recognised by police. In practice it means that they have to specifically be looking for you.