"A 56-year-old federal law requires companies that ship cigarettes across state lines to release the names and addresses of their customers to taxing authorities in the purchasers' home states."

You should check on this - Costco knows your home address and if they have to report you you may be required to pay BOTH SC and NY taxes on any cigarettes you purchase out of state.

I'm not an attorney but my read is

This is the 1949 Jenkins Act and it appears to only apply to delivery sales of cigarettes into other states. It does not appear to apply to Retail / Pickup orders.

I would suspect this law is only in play if Costco ships cigarettes for delivery across state lines. Specifically they could not charge SC sales tax and would have to physically ship the cigarettes and indicate on their invoice the order was delivered in NYC. I would not be able to pickup the order in South Carolina if this were a delivery sale.

I am convinced this really simple order method is no loop hole at all but a legitimate retail sale for merchandise ordered and paid for in advance for customer pickup. .

What I decide to do with my property once picked up is really no ones business as I am not in the cigarette business.