What the supermarket does is illegal. They have no right to fine your friends or anything. At most, they can let your friend buy that bottle of coffee. Those are the overlord clauses. You can complain to the consumer association or report to the industrial and commercial department. Even if the police station handles it, it can only educate your friends and there will be no criminal record. Because your friend's behavior is defined as theft at most, but the minimum standard of theft is 1000 yuan, and your friend is not yet 18 years old. Even if there is such a crime of sexual violence, it will not be convicted and punished.
You can negotiate with the supermarket from the beginning to see how to deal with it. If the supermarket is tough, it can be handled according to the above method.