I think that the birth plans, if they are to be any use, need to be far more specific. Eg instead of saying "I prefer not to have an epi" it would say that and then continue "if I request epidural anesthesia I would like to be encouraged to use [a change of position, water, heat packs, counter pressure, guided imagery, breathing techniques as practiced previously etc etc whatever the woman prefers to try] I would like to wait 30 minutes/another 10 contractions/whatever before reconsidering having the epi". Or whatever you like. The midwives and other staff should not be put in the position of having to make the decision for the woman.