Excuse me, the bottle cap fee in wine promotion, what is "open cover" and what is "hidden cover"?

In fact, Ming reform can also be called corkage fee, which is the threshold set by hotels or restaurants in order to let customers bring their own drinks and let you buy their drinks. You know, a large part of the hotel's profit is on drinks. Who will make it if you bring him here? Charging corkage fee belongs to overlord clause, which is prohibited by Consumers Association, but many hotels turn a deaf ear.

The so-called secret set is that the hotel gives the waiter a commission when selling a certain kind of wine. This is called a secret set!