I could totally see a hotel not allowing outside food or drink even in a room. I was helping run an event at DEFCON this year and apparently the Rio was fining

I could totally see a hotel not allowing outside food or drink even in a room. I was helping run an event at DEFCON this year and apparently the Rio was fining the conference for people in the conference area having "outside food or drink", especially alcohol, and "outside" meant "not purchased from the conference area concessions" - stuff from other parts of the hotel/casino wasn't okay.