Very dangerous in my opinion. Even more so approaching an intersection, you don't know who's going to come turning right on you (bike, ped, car...).
Even if it were legal, I would never ride on sidewalks, either. I don't want drivers to even start thinking of me as a pedestrian... Also I generally see sidewalks as a dangerous place for bikes, too far off to the right to be in the field of vision and field of conscience of drivers...

