This happened over the weekend.  I think this was debated a few years back (but then again what hasn't been? 

 ), but I can't find it.  USSSA game, but all rule interps are welcome.
     Mary has been pitching for 3 innings. In the middle of the 4th, Sally comes out to the circle, picks up the ball, and throws a warm up pitch.  Coach then tells Sally to go to right field and for Mary to throw the remaining warm ups. No substitution was ever reported/made.  Any violation?
     My partner said there is a slow pitch rule that would require Sally to pitch to at least one batter after throwing the warm up.  I felt there was no fast pitch rule to support that interpretation, especially during the dead ball situation with no substitution made.
     USSSA 6-1-L and Fed 6-2-5 mirror each other in addressing warm up pitches, but I don't feel either specifically indicate who is entitled to throw them.  NCAA 10.19.3 is quite clear about a warning, then penalty (coach ejection) when this happens.  But even they don't state that the non-pitcher who throws the warm up must now become the pitcher.
     What do you think?