I don't know the answer to your first question, but if you pay for the chairs there's no obligation to purchase food or beverage. That said, since there is a restaurant and bar on the premises, I (and this is just my opinion) think it's inappropriate to bring your own food and beverages to the premises. In fact, I believe I read that someone said they have a sign that prohibits coolers. This is a high-end beach resort, and their goal is to keep it that way.
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