WHY THE OBVIOUS FIXES DO NOT REACH

Escrow works. It just is not there.

The platform answer is an intermediary holding the money until delivery is confirmed. It works, which is why every large marketplace does it, and it exists nowhere outside those walls.

• Two strangers have no structure

  People who found each other in a hobbyist group are not inside anyone's marketplace. The protection that would solve this is a feature of a venue they are not using.

• Building it means becoming a custodian

  Holding everyone's money to solve a coordination problem turns you into a payment institution. We are not one and do not intend to become one.

• Meeting in person is the workaround

  It works and it costs both parties an afternoon, restricts every sale to one city, and fails entirely for anything that has to ship.

• Someone always absorbs the risk

  Usually the party who wants the deal more. That is not a market clearing efficiently, it is a market where trust is priced as a discount.