Except for the bars that they have elsewhere in the park. :eyeroll:
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Except those aren't cartoony outdoor themed bars--Finnegan's and Chez Alcatraz are located in locations squared off from the rest of the park. The environment is more controlled and less busy, making it easier to monitor guests and drinking, etc. Managing a bar isn't as easy as serving people liquor--quite a bit of work goes into it. Running a bar in the middle of a main thoroughfare isn't a good idea.
In any case, food and drinks, not alcohol, is what makes up the majority of sales in a theme park.