Hey Ang,
From my experience, when a pitcher starts to get upset or frusturated I go out to the mound give her a little pep talk/ confidence boost, maybe switch up the infield, but it's ulitimatly her decision how she will react to the circumstances of the game. She has to choose her attitude...
I am a second year coach from MN. I coach 7/8th grade girls and our run rule is 6 runs or 10 batters, which ever comes first. It works really well, it keeps the innings moving and the game more fair.
Katie M