"To solve this, yes theoretically you could have a trusted third-party intermediating, but who would that third party be?" A non-profit to start with given a s

"To solve this, yes theoretically you could have a trusted third-party intermediating, but who would that third party be?" A non-profit to start with given a startup is focused on money and growth. They almost always get more evil or acquired into evil over time. The nonprofit is chartered and/or contracted with standard provisions to prohibit certain behavior. They have a traditional crypto + database + published ticket log w/ optional apps as I described. Whoever is running it registers the event, they describe the constraints such as ticket numbers/pricing, that summary is posted by ticket mediator for all to see, each purchase generates a unique ticket in the database signed by central app, buyer's app plus mediator's web site shows decrease in tickets available, a log optionally shows a ticket ID (maybe hash) added for each ticket purchased, optionally saved onto append/write-only storage (DVD-R's) for certain amount of time, and any claim in court can pull the data to check payment records vs buyer's income on event vs database contents vs published log. All of this can be done on one server with an application server and a database since performance requirements will be low. Especially if HW-accelerated crypto in standard CPU's are used. And, since I haven't seen a mention of this, make sure there's an open-source verifier w/ patent license + the log itself is Creative Commons w/ Attribution. "If this were a product created by a monopoly with 80% market share" That's what your startup intends to achieve by creating and dominating a new market. Startups 101. My idea can be done by a number of organizations copying the same template for business, legal, and tech. They can do it for-profit based on reputation, non-profit set up to not legally be allowed to assist malicious behavior, or something in between. I'd trust my model so long as it was auditable w/ all the logs published. Organized crime is a crazy-strong threat model that might still forge things by coercing people to forge things with some gains between the event happening and my model detecting it. That's unavoidable but your model or mine will reduce risk a lot. Mine reduces operational risk with proven components.