Labor & Delivery Deck + non-OB cases in OR = 2 frontline anesthesia providers on call.
Example: you're on call and Dr. Takeallnight brings a belly case to the OR. 2 hours into the case with no end in sight, a laboring patient has a prolapsed cord necessitating a STAT c-section. There is no way your gen surg case is going to finish in time for the 30 minute rule, much less in time to actually save the baby. Some would argue that it could be defensible to leave the intubated, "train tracks" patient with the circulator RN and tend to the crashing C-section. Others would argue that the C-section can be done under local. No one would argue that this is an ideal set-up.
Example: you're on call again with Dr. Takeallnight and this time it is an epidural that needs to be placed. You decide (wisely) not to leave your intubated "train tracks" patient to do an epidural. The patient delivers without an epidural. End of story? Maybe. Unfortunately, said labor patient was the daughter/wife of a hospital board member/influential surgeon/local politician/you name it and they are now out for a pound of flesh - that pound of flesh would be yours.
I'm sure there are many practices out there that cover OB and non-OB cases with one call doc. I'm glad that I'm not in such a practice.