I assumed that franchise locations got reimbursed for coupons/point redemptions/etc, similar to when a franchise restaurant accepts a gift card and is reimbursed by corporate for it.
The whole situation is very odd. Especially that a local franchise would be hurt so much by the coupons that they'd throw someone on the DNR list, especially someone who obviously works for a corporation that rents enough to get stacks of coupons and would (presumably) have a contact at corporate to reach out to when a location overreaches. I know we've only heard one side, but if this is true, I'd hope Avis takes firm action against the franchise.