The cops around here in NSW Australia are aware that the bicycles power assistance has a legal limit. It was 200 watts ... but I believe it has now been made 250 watts (makes those old odd 3 wheeled things legal .. forget the name). They do get some people with those added on two stroke motors.
I don't know what other places have limits ... but I'm certain they are around.
There is an electric power thingy you can add here that meets the limit, but have an easy work around to give substantially more power. I think the cops will just look for the speedsters - if your too fast (including up hill) then they will look at you.
On a tour - you'd all ways be after a power point.
For commuting they would be fine (power point at home and work