I know that the same people own the Quizno's in Clayton and Smithfield. They are super nice folks, so I am inclined to give them the benefit of the doubt. The last time I was there, probably 2 months ago, they had signs up that stated they didn't accept coupons. Try not to hold it too much against them if they weren't able to take them.
The location in Garner accepted them gladly and when I mentioned that the store in Clayton wouldn't take them, she mentioned that she hoped by accepting the coupon, she'd secured some future business from me. I told her she had. As far as I'm concerned, if you're operating a franchise, then you have to operate by franchise rules. And if the corporate office says take the coupon, then you should take it. Let me know what the final resolution is with corporate, I'm interested to see.