Although I am not a lawyer, my understanding is that in general business law, the sender is responsible for the shipment, UNLESS other terms and conditions have been agreed to. As the sender your are responsible. If the shipment does not arrive, it is your responsibility to make good.

The smart thing to do is to explicity agree to shipping terms as part of the deal. When I sell on eBay I use the following terms: The cost and method of shipping is the responsibility of the buyer. Insurance is optional but recommended. If the buyer does not take shipping insurance, it is at the buyer's risk. With these terms in place, there is no ambiguity about who is responsible if the shipment is lost or damamged.