I didn't research birth at all with #1, I just figured it'd be fine since all the women in my family do NCB and many work in hospitals .... And we did really well, no interventions/issues (we have a great OB) -- I didn't even realize that I'd been given pit for third stage 'til a couple years later (I've heart conditilon that requires I have IV abx during labor).
When I talked about it with the OB, he said that it's hospital protocol and standard procedure for most OBs, preventive of hemorrhages, etc. I shared some research that some of the women on this board had shared on it (including WHO's statement that there is no reason to give pit preventively in the 3rd stage, that administering it "as needed" if seeing hemorrhage was more effective). He said he was comfortable with me not getting pit during the third stage, as long as I was comfortable recognizing that if he saw an emergency developing, he would need to act.
We ended up doing delayed cord clamping and natural delivery of the placenta. I couldn't interest SJ in latching 'til after the placenta delivered on its own with no medical intervention (No tugging! Wow, that's so not safe, I'm horrified to hear of it being used).
I was busy with babyloving, but dh said that one of the nurses opened pit and rushed over to hook it to the IV and OB was very abrupt with her. He told her to get it OUT of the room, that it wasn't on my birth plan, I didn't require it, he didn't request it - and that it had better NOT show up on my bill, either. (She said, "But I opened it!" as if that would make using it OK). He told her to throw it away elsewhere, it wasn't getting used.
I wish assisted homebirths were legal here, but in the interim I do like my OB. I think he goes with the status quo unless someone suggests otherwise (like me) but he's very pro-ncb, pro-bf, etc.
In terms of consent - sure, it's supposed to happen, but it's not much informed consent here. Mostly the doctors/nurses say, "I need to do X now, OK?" And I think most parents are so overwhelmed/intimidated/uninformed that they don't know to question (or even realize it's happening, like me with my first).