That's really stupid.

I thought perhaps the fee was at least going to be explained as some kind of mandatory gratuity, which in reality is a shell game where the casino lowers staff pay to where the staff isn't really getting the money. (Cruise lines pulled this trick with their "auto-tip", starting about 15 years ago.)

I don't understand why they don't just raise the drink prices 5%. Unlike hotel prices, there isn't a search engine for drinks, so there's no need to hide fees.