Here are some possible answers (with the help of a few of the mini bottles of gin):
The Mini Bar Magicians
First, let's address the obvious: hotel mini bars are operated by a secret society of Mini Bar Magicians. These enchanting individuals are known to perform the vanishing act of snacks and drinks with finesse. With a flick of their invisible wands (or perhaps just a master keycard), they make everything disappear faster than you can say, "I'll have a bag of peanuts."
Staff Snacking Spree
It's a well-known fact that hotel staff members work hard to ensure your stay is pleasant. But perhaps they also snack hard to have the necessary energy to make sure your room is impeccable? Is the mini bar a convenient snack station for them to recharge during their busy shifts?
There's a long-standing rumour that hotels are often haunted by ghostly gourmands who have a penchant for gourmet treats. These invisible epicures sneak into your room while you're away diligently tredding the art fair concrete floor, and indulge in a fancy feast. Beware of spectral voices whispering, "where's the caviar?"
Hotel Room Déjà Vu
Sometimes, the mini bar is empty because you've already been there the night before, had a few, topped-up by that late night gallery party to meet the artists (code for have another few drinks) and dragged yourself to breakfast against all your natural Circadian rythms. Time-space anomalies are common in hotel rooms, causing you to briefly occupy the same room multiple times. Your earlier self may have already devoured the mini bar goodies, leaving you with nothing but the bill to remember them by.
In conclusion, the enigma of the vanishing hotel mini bar items remains unsolved. While we can't say for sure where all those snacks and drinks go, one thing is certain: it's a mystery that adds an extra layer of intrigue and amusement to your art fair visit. So, the next time you find your mini bar empty, just remember that you're in the midst of a cosmic conundrum that we all experience, when we are finally allowed to take our room key, at an ever-later check-in time!