[AtlUmpSteve]

I use the driver's ed concept of "right of way" when teaching obstruction/interference. The rules give the right of way to the runner in all but two situations; defender in the act of fielding a batted ball and defender in possession of the ball.

Just like another driver cannot inadvertantly swerve into your lane and cause a "train wreck", the defender cannot impede the runner, even if inadvertant, or even if "have to get the ball". If a car cuts you off because they were in the wrong lane to make a turn, do you write that off as a "train wreck"? Of course not!!

If your insurance company would pay the claim, it's your fault; period. If the defender doesn't possess the ball or is the one protected fielder in the act of fielding a batted ball, the defender must avoid impeding the runner. That simple.