Policy vs Brains
Just to clarify, from the ops manual, the responsible service of alcohol policy states that multiples of drinks are not to be served. HOWEVER, common sense would dictate as has already been stated, that you would use your JUDGEMENT in a case like Mrs SO. Unfortunately, some CC lack this, but if they thought there was an issue they should have gone to their supervisor.
That aside, no one should be publicly humilitated and subtlety is the key.I am sorry for her bad experience.
BTW regarding the exit row briefing, sounds perfect to me. I would however be very HAPPY that all the answers were known, and think of that person should an emergency arise....