Who paid for the shipping? If the buyer agrees to pay the shipping costs they are in a much better position to specify how the equipment should be packed and sent. If you want it double boxed and no-peanuts, then make it part of the deal.
Respectfully, everyone should read the FAQ guidelines I referenced above. They are detailed, specific, and if followed will mitigate pretty much any problem that comes up. Per the guidelines, who pays for shipping is negotiable (ie buyer or seller will pay), but irrellevant to the question of who's responsible for safe packaging and shipment. THAT, is always the seller's responsibility. I personally will not deal with a seller who doesn't subscribe to this rule.