Solution
The vet offers the shopper a free product in return for signing up to a CRM program. If the shopper prefers not to, but is interested in the product the vet offers them a discount to be claimed as cashback by the shopper. In both cases the shopper submits a unique code that identfies the vet. Valassis validate all claims, rewarding the shopper and maintaining a record of sign-ups by each vet, entering them into a reward program.