The question becomes...what store is it and does the person living in NYC have that store in their home state? For ex: Say you are buying from Gap. If there is a Gap store in NYC you will pay the tax for the county that person lives in. (remember taxes vary from county to county - at least in the state in which I live) If there is no store in her state, she will not pay tax.
I suppose there can always be that rare circumstance where an SA may skirt around it somehow, but it is rare.
There is one other thing...some states still expect you to be honest and pay the tax on your own, but that does not happen. KWIM? There will be something in writing that says certain customers in certain states pay "X" taxes and others are responsible via their own state laws to pay appropriate taxes.