In my town we really only have bike lanes on the two main roads that go up and down the bulk of the city, and they ride dangerously close to lines of parked cars. I was riding downhill once when someone opened their door in front of me without looking -- luckily I managed to get past, but had they opened it a few moments earlier I would've slammed into it and possibly fallen into traffic.
Another time I was riding down a street without a bike lane. There was a row of parked cars on the side so I was rode roughly a door's length away from them, enough to keep me safe but taking on enough of the lane that other drivers wouldn't be able to pass without driving in the opposite lane. I hear a car suddenly rev up behind me and blare their horn as they sped past, sideswiping me and almost knocking me off my bike. I managed to confront the driver at the next intersection, "Hey were you trying to kill me?" "Yeah, I was" (he had two kids in the car too)
Cones are a smart way of tricking people into respecting these boundaries, but I wonder how long it'll be until drivers start violating them when they realize they're not official or the city starts removing them. In the meantime I might get my own cones though...