At any one point in a day I'm a pedestrian, cyclist, and driver. I regard sidewalk riding all about common courtesy and respect. It's the almost the same kind of courtesy I hope from drivers when I'm on the road, and the same courtesy I expect from cyclists or scooters or skaters when I'm walking or running on sidewalks/footpaths. (Speaking of which, skaters have the potential to be a menace to pedestrians, but they certainly can't be skating on the road.)