Yesterday I looked at today's digital-wallet implementations & concluded that I wouldn't be able to build a drop-in replacement for any of them. Apple's closest since its local files (in a simple public format) rather than a webservice, but details on how scanning your phone works aren't public.
Hardware isn't the issue, NFC chips are extremely cheap!
Most events, stores, etc should be satisfied with me implementing NFC Data Exchange Format to hand a copy of the digital ticket over.
1/3?