- user signs up
- user registers x supported payment accounts (Paypal, Venmo, etc)
- when a user wants to pay another user on their site, you send them to the appropriate payment provider with the details of the other user
- take confirmation from user that received payment and use it to update "trustworthiness" scores for both users.
This seems like it could work as a way to sidestep some of the legal requirements?
Though the amount of value the OP's company offers is a little lower (since you're not handling payments), I think the other benefits (discoverability, concentration of information, etc) that patreon offers are still seemingly on the table. Fraud of course is still an issue, but the upside is you can punt that to whatever payment provider they specify.