[Zepp]

I know that the OP was for Fed rules but here's a case play from a different rule set.

USA Softball - March 2012 Plays & Clarifications

PLAY: One out R1 on 1B. B3 swings and misses at strike three. B3 turns to walk back to the dugout as F2 realizes that R1 is stealing 2B. F2 steps forward to throw R1 out but stops in the middle of the play because B3 is in the way. R1 goes into 2B uncontested. When all playing action has ceased the coach of the team on defense asks for time and comes out to ask for an explanation as to why the umpire didn’t rule interference on B3

RULING: R1 is safe at 2B and B3 is not guilty of interference. Rule 1 Interference, Rule 7, Section 6P or 6Q: The batter is out: When hindering the catcher from catching or throwing the ball by stepping out of the batter’s box or when actively hindering the catcher while in the batter’s box. In this case the umpire judged that the batter did not impede, hinder or confuse the defense from executing a play. If the umpire had judged there was interference since B3 was already out then R1 would have also been called out. Rule 8 Section 7P