The only weekend when casinos did not make a profit, in the entire history of Las Vegas, was when the annual U.S. statisticians conference was organized in Las Vegas :)
The variation I heard was the the American Chemical Society (ACS) held their 1997 meeting in Vegas. The casinos didn't make enough money from the 13,000+ people who were there, and don't want the chemists back. Checking now, there hasn't been an ACS national meeting there since then, and the schedule, which goes up to 2019, doesn't show any future meetings there.
For what it's worth, neither does the American Statistical Association.
lol. Mine was told to me by a chemist. Did a physicist tell you the APS version? Looking at the APS calendar, they also have no upcoming meetings in Vegas.
I don't see how this makes sense. The casino's odds are always not in favor of the players, so the more the merrier from the casino's POV. Even if you're a card counting wiz, the margins are pretty poor and you're easily caught.
I imagine the real problem would be crowding your casino with people who just showed up for the buffet but refused to gamble.
I think your latter assertion is the point - the statisticians refused to gamble and many of the hotels' services are provided at a loss to help bring in gamblers.
Many businesses are run this way - restaurants make a loss on food to make their margins on drinks... I wouldn't be surprised if casinos make a reduced profit (or even a loss) on alcohol so as to make a profit on the gambling.
Casinos will comp you a room, meals, drinks if you gamble just the right amount, and it's sometimes possible to get +EV once you factor the "value" of these things into account. No card counting required.
The only weekend when casinos did not make a profit, in the entire history of Las Vegas, was when the annual U.S. statisticians conference was organized in Las Vegas :)