But they are getting a benefit. The reason the runner is on first is because the ball was thrown away. And he's still on first base. By marginally shifting his shoulders towards second base doesn't put him on second base.
It's not like he was caught in a rundown.
It's not that he marginally shifted his shoulder towards first base. It's that he made a clear attempt to go to 2B. You can actually run inside the line and not be tagged out. But you can't make a move to second without risk.
