Good real-world example for the kids here. This happens with some degree of regularity. Not common, but not unheard of.
We all know the ASA guidelines. We all (I hope) buy into the guidelines. So, should be a no-brainer, right? In residency any p!ssing match will be won by the more senior resident on either side, or by the louder/stronger attending involved. But private world is not quite the same. Recall everyone, in the private world the administrators usually kiss surgeon ***** because it is they who bring the customers (patients) as fertilizer to the cash tree (the OR). We are symbiotic beings who must be part of the tree fertilizing. In other words, we are a necessary evil, and all parties know this.
Heaven forbid this is your first case in private practice, 'cause the surgeon will form a very strong opinion of you based on this case. Whatever you choose to do, he will "brand" you based on that. If that is the case, I would ask one of your new colleagues for assistance in the form of a second opinion given in front of the surgeon. Trust me, if there is any such thing as "surgeon request" at your facility, you do NOT want to be known as "The Case Canceller". If you have a pre-existing (hopefully solid) relationship with the surgeon, your job is much easier here. Either way, as has been pointed out, if the patient aspirates, you are dust. Same surgeon who pushed you to do the case will plead ignorance as to the NPO guidelines, or else defer to your judgement (and say as such in a deposition).
So, all that said, what would I do? I would first remind the surgeon of the NPO guidelines and ASA recommendations, tell them of a colleague's experience with an aspiration, and then bounce it right back to them. Namely, I would say that since I am not a board certified surgeon, I cannot state just how "emergent" this case is or isn't. Thus, if the surgeon wishes to proceed with this case as it is emergent, that I don't care if the patient still has the cheeseburger still in his hands (yes, I actually do say this) we shall proceed with the case. I of course indicate that I need to know if it's an emergency or not because that allows me to justify my actions should anything go poorly.
In 14 years of private practice, I have encountered this scenario maybe 10 times (where the patient with full stomach is not a true emergency), including last week in a surgeon-owned outpatient facility. Never had to do the "full stomach" case except when legitimately an emergency. Seems that everyone knows the real answer in these situations, the surgeons just sometimes try to get away with one.
What did you do?