runner interference with a batted ball

Question
The umpire in a recent junior varsity softball game played on the east end of Long Island, NY called my daughter out for runner interference with a ground ball. There is no dispute that my daughter was simply running in the base path from first to second base, and during this process ran in front of a fielder (the second baseman) who was trying to field the batted ball. The fielder at the time was playing back, well behind the basepath (that is, the fielder herself was definitely not in the basepath).

I checked the official rules of baseball. The baseball rules are clear that the above situation does not constitute runner interference with a batted ball. In baseball, a runner simply running in the basepath has a clear right to run in front of a fielder who is behind the basepath trying to field a ground ball.

After the game, when I (politely) asked, the umpire defended the call he made, by saying that in softball the rules are different and that the runner must stop, or otherwise avoid running in front of a fielder who is behind the basepath trying to field a ground ball. The umpire took a quick look at his rulebook, but was unable to find anything on point.

Was the umpire's call correct? Are softball rules different than baseball rules in this area? Or did the umpire in this situation make the wrong call?

Answer
This is a great question!  I'm going to start with some friendly advice:  Baseball rules can and generally are different from softball.  There are many examples but you have to be careful when comparing the two.  When you ask a softball umpire about softball rules, try not to bring up baseball rules.  In my experience fast pitch softball umpires do not umpire baseball and can get irritated when comparisons are made between the two rule books.

I also want to define a few softball terms for you:

Base Line - A base line is an imaginary direct line between the bases.

Base Path - A base path is a direct line between a base and the runner's position at the time a defensive player is attempting (or about to attempt) to tag a runner.  
(Note from Rich:  The base path isn't established until a play is being attempted or about to be attempted on a runner)

Interference - Interference is the act of an offensive player or team member, umpire or spectator that impedes, hinders, or confuses a defensive player attempting to execute a play.  Contact is not necessary.

The situation you describe points to the word "judgment".  This word can easily cause cheers and at the same time heartburn for players and fans alike.  First of all as a base runner you must always allow a defensive player to make a play on any batted ball.  To have interference, the offensive player, in the umpire's judgment, must be impeding, hindering, or trying to confuse a defensive player.  Now you notice that the rule doesn't say anything about intentions.  The player does not have to do any of these things intentionally to get called out for interference.  So if a runner accidentally bumps a shortstop in the middle of throwing to first and the ball sails over the right field fence guess what?  Dead ball, interference, the runner is out.  Also notice that there is nothing about the runner stopping or going around a defensive player.  There is nothing in the rules that indicate this must be done.  All the runners can do is to try to avoid a defensive team's attempt at a play.

Since I wasn't there I didn't see exactly what happened so the above is all I can tell you.  In the umpire's judgment he saw interference.  I've given you everything you need to make your own determination.  Judgments can not be appealed and at their basic core consist of fair, foul, ball, strike, safe, out.

Thank you for the question!  I hope this answers your question, any additional comments or questions please ask!