If I test positive, I will be put on IV antibiotics in labour. That is just they way they do it over here. That rules out the homebirth, although I can certainly still have my midwife deliver the baby at the hospital. We have a total health care system, so I am getting what amounts to a private midwife in your system (if I understand it right, since I can deliver at home.) but it is publicly funded. I can choose an OB, GP, or midwife for my prenatal care, and deliver at home, in hospital, or at a birth centre. (If they had one here - small town!)
I am going to discuss the options a little more with my midwife next time I see her, but I think I will see if she is OK with just treating me if I end up being high-risk, and letting it be otherwise. All babies are carefully monitored for signs of GBS after birth anyways. If my midwife recommends the screening, I'll do it. I do trust her judgment.