The wobble thing is usually a setting to turn on. It's not a perfect solution, but the line where the bars live won't be the issue that the large dark space might be.

I haven't spent much time being concerned enough to chase down the details because I don't watch much 4:3. If I am forced to do that over a couple of hours in a row, I'll usually change the channel during a commercial to a full screen and eliminate the possibility.