Like get an inexpensive tablet and mount it in view of the cameras and have it cycle through:

• Random plate numbers in the “license plate” font just to mess with their database?

• Police license plates?

• State politicians license plates?

Hit up local government auctions. Sometimes they sell 2-4 computers in a lot, sometimes they sell 157. I got 4 Lenovo mini computers for $34 each in an auction a while back. They only needed hard drives.