[leichtgewicht]

So I only see two major downsides: 1) I basically I have to verify/transact every "printed" money the moment I get it - preferably using a smartphone - in case someone else has a copy of it and "takes" it first. Copies could be made with any high-resolution camera. 2) If the money travels from A to B to C in paper shape and the digital transaction will be from A to C then A will know that B has done business with C.

[cydrobolt]

Yeah. Right now, it is largely based on trust. We're hoping to implement some kind of one-time "seal" and new token that a user can verify after receiving a bill to ensure that someone else can't activate it with a picture or by saving the token. That obviously comes with the downside of making it more difficult to transfer.

As a proof of concept, and being based on Venmo, I think it is and will be largely based on user trust as long as the bill creator keeps the funds (Venmo allows no bot accounts).

[BHSPitMonkey]

Unless the note changes hands additional times between B and C.

[leichtgewicht]

Point taken. It then just becomes a statistical probability of how many steps between A and N. Considering that everybody using this system better have 0 steps (former point made) 1 step is about the furthest I would hope. But you are right: there could be more steps.