The only way in which this makes sense in international is something like courier flights. I don't know if this even really exists in the form it used to, but there used to be small-scale services that would buy regular airline tickets (in advance but transferable) and then resell the seat but not the luggage allowance for major city pairs like NY-London. A person who can fly on short notice with no baggage allowance gets a cheap ticket, and the customers get their essential items delivered more cheaply than last-second air freight.

A key element is that the passenger was contracting out their baggage allowance and so didn't ever interact with the items - they never even saw it. So no liability.

Surely that's dead now airlines are charging to have hold luggage at all.