Re: What could possibly go wrong?
"As a side thought, what happens if they drive across state lines and that state doesn't yet like e-ink?"
I expect it is covered by Interstate Commerce laws the same way that one state can't cite a person with out of state plates if those plates are properly issued and registration paid.
The fun will come when the plates fritz out and an out-of-state LEO has to try and look up the car's registration manually. I have a feeling that they don't bother too much with cars from another state, but would have to if the ePlate was blank or read "biteme".