The point about the danger of this behavior being related to intersections is quite valid. However, no one has mentioned driveways. This is more of a danger than the intersections in my mind, the same issue with not really looking to the right when turning right is a big one, regardless of whether or not the driver is responsible. If you're going to ride against traffic on the sidewalk you should be well aware that you could die from this and proceed accordingly.
Had a salmon yell at me to pay attention because I was looking down at my chain for a moment, never mind that he was on the wrong side. He almost t-boned my wife and I a few nights prior to this, doing exactly what other posters here have described. He wasn't riding on the sidewalk, so this story is a little off topic, but the fact that I haven't seen him in months makes me wonder if he finally got hit.
So, in short, be careful when on your bike.