but if you bunt because none of your batters have had much success against the pitcher, you've just given up a chance to score the run and are now left with only 2 chances. Guess what? you still need to have one of your batters do something against that good pitcher to get the run in. A wild pitch is a possiblity but those are rare, especially if the pitcher is doing soooo good. And the last chance(with 2 outs) would require she reach base safely. How many times have you seen Albert Pujols, David Ortiz, or Arod, etc, bunt in a similar situation? I know thats baseball, but the situation is not much different. Same needs, same rules, same situation, just with everyone on a much higher level there. If you're so convinced your next batter up cannot even put the ball in play then of course bunt. But if she is 0-3 with a couple of groundouts or a flyout I give her a chance to win the game or move the runner up anyways possibly by just putting the ball in play. By having her bunt, you are absolutely giving up one of your chances to win the game right there. I believe its not as cut and dry as simply calling for the bunt every single time in that situation, but we're all different. Sometimes being too conservative is not a good idea.
as for defensively, again it depends on alot of factors. Who is up for them? How have they done? How fast is runner on second? Hows our pitcher doing against these batters? This game would be boring if the same thing is done in every similar situation. Thats what makes the game fun. There are multiple ways to go about it and none of them guarantee anything.