[brutusborn]

The only alternative I can think of is to use escrow, which probably isn’t attractive for illegal activities and still requires trust.

[tracedddd]

Escrow was pretty popular on Raidforums, high reputation forum users would not only escrow transactions directly but also do things like pseudo-publicly validate or invalidate claims by checking a sellers data or tools against their own collections (presumably the benefits of being a professional hacker escrow and seeing lots of data).

[Terr_]

I recently read a book [0] that goes into that and how--much like biological parasitism--sometimes you have frauds upon frauds.

[0] Lying for Money: How Legendary Frauds Reveal the Workings of Our World

[CodesInChaos]

You can use 2 of 3 multi-signatures to reduce trust requirements.