When customer attempt to purchase alcoholic beverages who decides whether the sale is legal or not?

It is the responsibility of the seller to ensure that the customer is of legal age to purchase alcohol. If the seller has any doubt about the customer's age, they are required to ask for identification. If the customer cannot provide valid identification, the seller should refuse the sale.

Here are some specific considerations that sellers must take into account when determining whether to sell alcohol to a customer:

- The customer's age. The legal drinking age in the United States is 21 years old. However, some states may have slightly different age restrictions. For example, in some states, 18-year-olds may be allowed to purchase beer and wine.

- The customer's intoxication level. It is illegal to sell alcohol to someone who is already intoxicated.

- The time of day. In some states, there are restrictions on the hours when alcohol can be sold.

- The location. There are certain places where alcohol cannot be sold, such as schools, churches, and hospitals.

By following these guidelines, sellers can help to ensure that alcohol is sold only to those who are legally allowed to consume it.