who is liable?
In theory the courier or their insurers are liable, but that's not the point. The point is whether you as the seller are held liable? Under eBay's rules, no you are not, but it doesn't always end there.
eBay now disqualifies purchase from its money back guarantee if the buyer sends a courier or any third party to collect it. Before this, buyers would often try to claim a refund from the seller even though it was their own courier who damaged the item.
However, buyers can still try to make a claim against the seller through their payment provider. Sellers don't even know how buyer paid eBay, but if by credit or debit card they can ask their card company to issue a chargeback. This can happen weeks or even months after the sale be sure to keep all the relevant information. In particular, print copies of relevant online pages and messages etc. in case eBay deletes them, when there would be no way to get them back.
