alt Hacker News> The problem is the police can make up intent just to mess with people. How easy is it fro the cops to say "You purposely splattered mud on you license plate" and fine you or put you in jail. Or even use it as an excuse to pull you over.
That's not the problem. The fact that intent is considered by the law is a good thing, because it allows you to use the defence "I didn't intend for the mud to obscure the number". Without that, the cops can just say "there is mud on your license plate" and you have no recourse.
Unfortunately you are responsible for making sure your plates are clearly visible while driving. Mud doesn't easily coat your plate to the point of obscurity, you either were driving in lots of heavy mud (clean off car before going back on public roads) or haven't cleaned accumulated mud off in a while (not adhering to making sure your car is road legal).
Negligence will still get you in trouble.