Well I'm not pregnant so I'm certainly not asking for myself. In my case with DD#1 I had been very clear with my midwives that I had already had two big babies and this baby would be big too. No problem they said. Sounds like your body can handle this. No worries. I had already switched from an OB to these midwives early in the 2nd tri after I was getting bad vibes from the OB. Fast forward to 38w when I was measuring 46w and suddenly everyone is nervous and wants a u/s for size which I foolishly agreed to. This came up with a calculation for 11.5lbs by EDD. I was not concerned and refused induction or c-section etc. That was all fine and good but I was given basically until just a few days after my due date to produce a baby or be transferred to the OBs. I was not interested in that at all. So I chose to give castor oil a shot instead. I had one big poop about five hours after I took it and had contractions start. Took a nap and woke up in labor. No massive diarrhea. No dehydration at all. Having had big time pit augmention with my first two and ended up with an epi because of it I would chose castor oil and a shot a natural labor over a pit induciont seven days of the week and twice on Sunday. I also felt very confident that if DD was not ready then the CO was not going to work. To me that seemed like a much better alternative than trying to find someone who would take me on at 39w4d while carrying a theoretically 11.5lb baby.
With DD#2 my mom had come all the way up from Louisiana to help out with the baby and DD#1 and this was my one shot to have help so yeah four days after my EDD I chose to try castor oil again. Again figuring it would work or it wouldn't and no big deal either way. I was having regular contractions but they were off and on. I thought the CO might help them stay more steady. I also walked a lot and drank lots of water. I did have more effects from it than with DD#1 but still nothing devastating and I did not become dehydrated. Did have different midwive who I had made very clear to them that I was not going to have a late term u/s and this would be a big baby and I wasn't going to agree to a medical induction or c-section. They said that was fine and they were true to their word.
In both cases I almost wonder if taking the CO had more of a mental effect than anything else like "Yes ok everything is ready to go. Now it's ok to let go and have the baby." In an ideal world my provider wouldn't suddenly flip 180 degrees at my EDD and I wouldn't have to worry about who was going to watch DD while I was in labor if I didn't have the baby while my mom was there. That's not the world I live in though. So that's great if some people have no pressure whatsoever to deliver the baby. Not everyone does. We seem to go back and forth on these boards either saying "nothing will work if the baby's not ready" or "OMG if you take anything or do anything that might theoretically cause your labor to begin then you're rushing your baby out." In the grand scheme of things CO seemed like a very minor intervention and it was one I was willing to use. I felt less sure about taking cohosh tinctures which for some reason seem to be given more of a "natural" pass on these boards. I took EPO too but that seems to generally be considered ok as well. It is always a nice reality check to come to MDC though where I get to be the soggy one because I took castor oil after my EDD. It really is just all about your POV.