For what it's worth, the Boosted Boards in the bike lane on Market St in SF seem to get along pretty well with bicycles. I think it helps that they are pretty zippy and don't take up an unnecessary amount of road space (like an electric moped does). There is more of a conflict when the Boosted riders hop on the sidewalk...
I think that's a good sign. A sign we're not only shifting from car-primacy but also to welcoming other modes of transportation.
Sidewalk, personally, I think they should be reserved for pedestrians primarily, with few exceptions (hand trucks, strollers, wagons, wheelbarrows, etc.)
