I'd like to assemble a system made of a tablet (10" android FHD) with an anti-theft stand and a (possibly) wireless printer.
Visitors will stand in front of the tablet, insert their email and name, a countdown will start and the tablet camera will take a picture of the person. A transparent GIF (or PNG) will be added to the photo (date, event, brand name) and the subject will accept and print it or retry the operation.
Eventually a SMS (or email) alert to inform each n (20?) photos, to advise going check consumables.
Plain, simple, unstoppable.