When I've seen it done, the MW puts a small hole in the bag during a contraction with the hope that the force of the contraction will break the water the rest of the way when the baby is at her lowest and hopefully the baby will stay down. I've seen it work very well. Mom was fully dilated for 16 hours but baby was still high and waters were in tact. It was a VBAC attempt and she'd been going for 40 hours at that point. In the time they knew she was fully dilated until they broke the water they did things to try to rotate the baby, baby moved down immediately, but still still had to push (with her urges) for more than 3 hours and eventually gave birth to a 9 lbs baby.
It doesn't always work and it is better for the waters to release on their own, but at a certain point, most people want to do something. What point that is, depends on mom's state and baby's health. In the hospital, they tend to start interfering too early (as soon as you get there), but for me, personally, after 48 hours of labor most babies are born and I would not want to get to 72 hours without a baby one way or another. That is definitely something you have to decide for yourself.
I just don't even know if creating a small leak instead of breaking the water is even reasonable. Sounds like she didn't know what she was doing. Here's why...there's already a ton of pressure on the amniotic sac even when you are not in labor....once your cervix starts to open all that pressure is pushing on that one area where there is some give. If you are squeezing a balloon (which is much thicker and than the amniotic sac) and you try to create a "tear" vs. "breaking"....I guess I don't even know how one would reasonably not 'break' it no matter how gentle or how small the hole is. Even if you did accomplish a small tear....one contraction is going to squeeze all the water out and break it anyway.
You know, that's a good point. I guess it just seemed reasonable at the time. I wish that my doula would have had more knowledge about that. I would have listened to her if she would have explained it. My doula, however, agreed (although hesitantly), with the midwife. That is definitely a big regret I had with my last labor. It was the one and only intervention I had (until the c-section), and I wish I could have taken it back. Thanks for that explanation, though. I'll be prepared if that comes up next time!
Also, on the chiropractic care and other body balancing techniques, I think starting before you are pregnant will give you the best chance if you have a severe issue.