It's very common to just have fake plates / registration, with the plan in the case of an accident to just bail out and run.
[1] https://www.wmar2news.com/homepage-showcase/how-md-drivers-w...
FWIW, despite all this the speed cameras have been effective at reducing average speeds at problem points.
[1] https://www.wmar2news.com/homepage-showcase/how-md-drivers-w...