I rented one of those on a little vacation up in Vancouver BC a few weeks ago. It was a hoot. Felt like a quality mountain bike, but just when it starts to feel like work, you get a little kick from the motor and off you go. It's like performance enhancing drugs without the strange hair growth...
Perhaps the police are pulling him over for the same reason he chose not to drive a car, he is not really able to drive or ride a bike safely on public streets. I'd go for a ride with him and watch how he rides. He may be in over his head and needs a bus pass more than an e-bike.
Another good...