This happened yesterday in the Dodgers/Diamondbacks game...I've never seen it before, but it makes sense.
It got me thinking that if this happened in a fastpitch game, all hell would break loose from the defensive side if the play was called correctly.
Look at the link and it describes different scenarios, including the play that happened yesterday with the Dodgers batting.
http://en.wikipedia.org/wiki/Fourth_out
Here is what happened in the Dodgers/Diamondbacks game:
Example: A missed fourth out
On April 12, 2009, in a game between the Los Angeles Dodgers and the Arizona Diamondbacks, the Dodgers scored a run because the Diamondbacks failed to record a fourth out. There were runners on second and third with one out, when the batter hit a line drive back to the pitcher. The runner on third scored without tagging up before the runner at second was tagged out. The Diamondbacks left the field, thinking that the inning was over and the run did not count. However, tagging the runner at second who failed to tag up was not a force out, so the run was not cancelled. After all the defensive players had left fair territory, Joe Torre talked to the umpire and claimed the run. There were no Arizona players left on the field, so nobody could tag third base and appeal that the runner had not tagged up. If they had done this before leaving the field, it would have become the actual third out and the run would not have scored.
I'm also curious if any of you heybucket blues have seen this play happen?