Actually I talked to my ob about this today.

She said that in her opinion the comments might be sensible of very obese women (BMI over 45), who are giving birth in the crowded public system. The rationale being that it is better to plan to have an epi given by an expert, during the daytime, than to have a registrar doctor trying to get a tricky thing right in the middle of the night if you really need one then.

Given the reports in the press about the state of public hospitals in Melbourne at the moment, and the fact that epis seem to be harder to get right for obese people in general, the ob's comments actually make sense to me.