
When I take my daughter to the local "run and pipes, play games, and eat pizza" restaurant, they stamp our hands to match. I also fence, and before each tournament, we get a stamp applied to our gear after it gets certified. You could do a combination of these with gear and users. Get some cool logo stamp with a number sequencer. Give each attendee a card and stamp the card, and then stamp a sticker on the major components. When you leave, they have to match up the card to the gear. PITA. Some might complain of getting stickers on their gear. Some might think its pretty cool.
Almost anything derogatory you could say about today's software design would be accurate. -- K.E. Iverson