In my opinion, we have fought long & hard to be respected as vehicles who earned the right to use the road. We can't have things both ways.
If a bicycle is allowed in a store, is a Vespa allowed as well? How about a 250cc dirt bike? Then going up in size, a 500cc bike? 600cc? liter bike? Hayabusa? How about a smart car?
Where do you draw the line?