I presume it will depend on the city. In dense cities, bikes on sidewalks are obnoxious and clearly a safety hazard (note: I am a biker in such city) I cities

I presume it will depend on the city. In dense cities, bikes on sidewalks are obnoxious and clearly a safety hazard (note: I am a biker in such city) I cities with very few pedestrians on sidewalks, it could make sense (especially if the sidewalk is large enough to allow for a split)