GrailOfThunder:   I remember when Jack in the Box was advertising their tacos at 2 for 99¢. No store in my area had them at that price - cheapest was $1.19 (course now they're even more, usually $1.29). I still bought them of course. I'm addicted. :)

Franchise would be the key defining concept here.  Unless you run with a very restrictive franchise contract setup, you in fact cannot guarantee that all stores will participate in your promotion.  You quite literally have no legal way to force them to do so as the franchising company.  Being a franchisee gives you certain legal rights that direct subsidiaries do not have, and deciding what to participate in and what not too promotions-wise is one of them.

It's not terribly optional.  If you demand certain aspects of control over your stores, they're going to be ruled branches not franchises, and the law will treat them that way.  Which means no charging people money to buy a store, no charging them for supplies, no charging them for every other damn thing you can come up with... in other words a real groin kick for the fast food system's cash cow.  Not gonna happen.

It's a lot like the, "Are they an independent contractor or an employee?" game.  If your franchisees are doing things like paying you for locations, training, and supplies, they're a contractor - and have the right ascribed to franchise operators.  If not, they're an employee, and you can't soak them for all that shiat.  This is why they do what they do - and why it's entirely different from say a grocery store - which is generally wholly owned.

/although Kroger for example does franchise some of their convenience store-type locations
//they don't do so with their actual grocery stores
///not aware of anyone else that does either, there's a lot going on in grocery that would make franchise a tough fit