With the Tennessee girl not tagging, she would have advanced easily to third on a tag because the ball was caught on the run on the warning track. If the ball had not been caught, she probably would have scored unless the ball would have bounced right back into the left fielder's glove. Still, second and third with one out is far preferable to getting doubled off. Because she likely would have scored from second if the ball wasn't caught, the correct play was to stay on the base.
This changes if one is on first base. If she had been on first, the correct play is not "halfway", but to go as far off of first as you can without getting doubled off if the ball is caught.
Whether it's that type of play, an infield fly or anything else involving baserunning, if a team doesn't practice it, most girls won't do it right. As we know, most girls have grown up watching little to no baseball or softball on TV and played probably no sandlot ball. Their entire universe of knowledge is what happens in practice and in their own games. It's little wonder that most girls are poor baserunners and have no idea what to do when an infield fly isn't caught or when a throw goes out of play.