1. Many, many stores are refusing Internet coupons because they are so easily photocopied or altered. Not just Target. When I do print Target.com coupons, I use color and take the entire sheet into the store with me.

I don't bother with other online coupons, even those from a manufacturer. Partly because of the issues I've learned about, and partly because our printer is "stupid" and we can't print wirelessly for some reason. (I'm saving a ton on ink, since my kids don't just print randomly any more. They have to walk their 'puters to the printer and hook them up. Lately, only homework is worth the effort. I'm in no hurry to figure it out.)

2. People who try to use store coupons plus manufacturer's coupons for the same item might run into some resistance. Again, not just at Target.

3. "LOGIC", to use OP's caps, isn't a part of a cash register's programming. The cash register, or computer, applies its programming without regard to age, race, religion, sexual identity, marital status, parenthood status, visible-tattoo status, or the method of payment you're using today. OP could see what needed to be done. Likely the cashier and the manager could see that, too. But nobody knew how to make the cash register override its internal "logic".

I remember that, at first, many people were thrilled that the machines just could not discriminate or "make mistakes". Now, however, we're finding that computers do indeed make mistakes, and that sometimes the human logic can indeed be superior. But the humans aren't given the right tools to make the situation right.