I am with you 100%, Here in Calgary we often have an asphalt bike path c/w yellow line down the middle turn into a concrete sidewalk and then 100 metres later it will turn  back into a bikepath.. I will get off my bike and walk if pedestrian flow is heavy, but I have seen sidewalks with no-one on them for days. Also there seems to be a game here where drivers attempt to get as close to a cyclist as possible if you are driving on the road with no marked shoulder.