Challenge
Paper stamp cards were lost, photocopied, or left at home. The chain could not tell who was close to a free coffee, and there was no way to invite a regular in when they walked past a quieter café. Morning traffic was strong; afternoons were slow.
Strategy
Stamp cards moved to Wallet Passes: nine coffees, the tenth free, with the live stamp count on the pass. A geo reminder fired when a cardholder came within 150 meters of a café they had not visited that day. Afternoon combos were pushed only to guests whose last visit was in the morning — so regulars were not spammed.