Totally agree with the drunk cliff jumping. And that's because the natural loss of balance from alcohol intoxication will cause awkward, painful and potentially paralyzing water entries!
That said, I suppose nobody should walk drunk. Or swim drunk. Or snorkel drunk.
But, how many people go on booze cruises/snorkel boats and have a great time snorkeling? If you aren't a strong swimmer, wear a vest. If you are totally ****e-faced, wear a vest. If you've had a few? Well, wear a vest if it makes you feel better....but if you are too drunk to swim, you are too drunk to snorkle and the decision to get in the water was beyond foolish....