Check out the link in post #19.
There is a very interesting article about buying liquor at Costco, and you do NOT need to be a member. Hawaii is one of four States that are listed, that allow you to enter a Costco to purchase liquor without having a membership. Of course, it also states that some employees are not aware of this policy, and you may need to call supervisor. They have to put in some "temporary" number for you in order to complete the transaction.
It may be more bother than it is worth, but for anyone who is after some amazing prices (compared to what we pay at home in Canada), it may be worth a visit.
And thanks to Wanderlust for supplying this information.