Flight Attendent: "Our records show you as a doctor. A man in second class needs surgery, now!"
Vatcationing Doctor: "And whom will be paying for said surgery?"
Flight Attendent: "Pay? What kind of horrid person are you?! You must help under the Hippocratic Oath! Now go!"
Vatcationing Doctor: "Oh, I must help for free? Well fuck you then. I'm going back to sleep."
Denial of aid. You'd likely be liable, at the very least get sanctioned, and might actually go to prison.
Can't the doctor ask to be.... free of any and all liability related to the event at least?
A simple fill out form beginning with...
"I understand that Dr. Doom is helping me/my loved one while he/she is on
vacation. I absolve Dr. Doom of any and all liability relating to the medical care provided me/my loved one on this ___ day of _____, ____."
Just hand it to the patient or a relative, don't say anything, go about your business of taking care of the patient. If someone gets angry over it, just stop working.
"Please sir/maam, do you think it advisable that we spend time arguing while you are/your friend is in need of help?"
Its a round-a-bout guilt trip way of getting people to sign it... Also, no 'coercion'. Do it all calmly for bonus points.
Also, never tell the airliner or anyone that you are a doctor of any sort when on vacation.
Being expected to do stuff sucks, it gives a better feeling when you point it out yourself instead of someone else pointing you out.