[chaporkar]

Couldn't have explained it better. Just one thought though: What if you buy it in a duty free shop?

[tomfakes]

Duty Free shops, I believe, are for personal use only. Gifts to family and friends are overlooked, but the limits are small enough anyway that you can't possibly give too much away - i.e. 1L of booze, a few bottles of wine.

[iamwithnail]

"Won't know, can't tell." Although you can't tell what the NSA might be able to tell border and customs... ;)