Is there a legal basis for some snack bars to post "no take-away drinks"?

According to Article 9 of People's Republic of China (PRC) Consumer Protection Law, consumers have the right to choose their own goods or services. However, the right of consumers to choose their own transactions should not be understood unilaterally and absolutely. Article 3 of People's Republic of China (PRC) Contract Law stipulates: "The parties to a contract have equal legal status, and one party may not impose its will on the other". This clause means that neither party to the contract can impose its will on the other party. As the main body of civil activities, operators also enjoy operational autonomy according to law. In a completely free market, unless it enjoys an exclusive or monopoly position, operators also have the right to choose their own transactions, and they also have the right to choose who to trade with, in what way and under what conditions. As long as consumers and business operators reach an agreement on the expression of will in the transaction and do not violate the prohibitive provisions of the law, their civil actions are legal and effective, and the legitimate rights and interests of both parties are also protected by law. As far as the behavior of "not allowed to provide take-away drinks" is concerned, the operator is not in a monopoly position, and his behavior does not violate the prohibition provisions of the law, and he has fulfilled his obligation to inform consumers in advance, protecting the other party's right to know according to law, and his behavior itself is legal. Does not constitute forced consumption. These snack bars are actually taking advantage of the law, and most ordinary consumers will not file a lawsuit for it. This lawsuit may not be won. So it is best not to choose such a place for consumption.