No, I did not know this existed though in Australia we have the dockets on the back of the till slips -or is this the same thing?
I don't use them as I use the Groupon type ones and get a lot of lunches for half price anyway.
I generally don't read things like that on boxes -just read what is in it and what chemicals, calories etc are in the food.
No one intends to read these sorts of things, but they are impossible to miss on the packets. They will be big, bright, and bold messages telling you about free tickets to theme parks or gift items, and then to see the back of the box/website for details. I assume, you just don't buy any brands that do that sort of thing.