Comment by __MatrixMan__

That requires a single source of truth for which names go with which tickets. Which is going to be a problem if tickets need to be transferred in contexts where users don't have internet access (but they do have local connectivity between devices) or in contexts where the venue doesn't have internet access. Or in cases where the single source of truth might be vulnerable to attack or doesn't have the resources to handle the load at certain times.

I don't have the solution explicitly, but it seems like it ought to be possible to do this such that PII need not be collected. Tickets could be cryptographic proofs that a chain of custody exists and meets certain criteria. The proofs could be constructed at transfer time and verified at admission, no servers in the loop anywhere. Yeah, we'll come up against the CAP theorem eventually, but we might find that the imposed constraints are workable.