~~~~~~~~ http://about.usps.com/publications/pub300a/pub300a_tech_021.htm A company sends you a gift in the mail — a tie, a good luck charm, or a key chain. You didn’t order the gift. What do you do? Many people will feel guilty and pay for the gift. But you don’t have to. What you do with the merchandise is entirely up to you.
If you have not opened the package, mark it “Return to Sender.” The Postal Service will send it back at no charge to you. If you open the package and don’t like what you find, throw it away. If you open the package and like what you find, keep it — free. This is a rare instance where “finders, keepers” applies unconditionally. Whatever you do, don’t pay for it — and don’t get conned if the sender follows up with a phone call or visit. By law, unsolicited merchandise is yours to keep. ~~~~~~~~~ Gift - something bestowed or acquired without being sought or earned by the receiver.
There's a difference between an unsolicited shipment and a solicited, but erroneous, shipment:
Q. What should I do if the unordered merchandise I received was the result of an honest shipping error?
A. Write the seller and offer to return the merchandise, provided the seller pays for postage and handling. Give the seller a specific and reasonable amount of time (say 30 days) to pick up the merchandise or arrange to have it returned at no expense to you. Tell the seller that you reserve the right to keep the merchandise or dispose of it after the specified time has passed.
Gifts don't have to be intentional
This is entirely incorrect. By definition, a gift must be intentional:
In order for a gift to be legally effective, the donor must have intended to give the gift to the donee (donative intent), and the gift must actually be delivered to and accepted by the donee.