How about not serving liquor to people in exit rows because they might become unable to assist in an emergency? How about the guy who climbed the 103 flights of stairs at the Willis Bld. with a prosthetic leg?

These things are by nature subjective. Me, I'd prefer the guy with the prosthetic over the guy who got drunk any day of the week.

That's why FA's and ultimately the Captain are empowered to make these decisions.