You can either provide your own liquor or have your caterer provide it or even half and half, but either way you have to have a caterer bartender serving it. You can not leave it out and let guests serve themselves.
The wedding I went to, the husband purchased the liquor, as it is not provided by the venue. The caterer or bartender must serve the alcoholic drinks. The bar designated for the drinks is pretty sophisticated.
The wedding I attended there is a walk up bar. I'm unsure if the bride/groom provided the liquor or if that was part of the rental
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