I think It’s a little off that the seller is confident enough to pack an item with the belief that it’ll be protected in transit, yet be unwilling to then send it. If it’s damaged in transit as a result of poor packing the liability would still be theirs. Personally, I avoid these adverts as soon as I see them.
I’ve been buying, selling and sending basses for years but nowadays I think the sheer volume of items being sent and the cost-cutting nature of the industry means they’re more at-risk than ever, and so I avoid it wherever possible.
The last bass I sent had the neck removed, which was much easier to send and secure too.