Drop an email. Seriously. I lived off free whoppers when I was in NJ simply by filling out the customer surveys on their website.
I'm pretty sure if it wasn't for those surveys, I would have died of malnutrition. I was worked like a rented mule and paid even less. In the entire time I lived with my uncle, we went to an actual supermarket ONCE. He bought steak, I got six cans of spinach and a bottle of red wine vinegar.
And got called a "bless'ed meatball" for my choices.
That was it. six cans of spinach.
Thankfully, customers did tip on the job. And since I looked like I was dying most of the time (I'm very pale, and turn bright red at the slightest amount of physical exertion) tips were good.
If the tip were snuck to me, a handshake with some cash, times were good. If the tip was passed to the boss (My uncle) times were lean.
Stores I frequent probably do not care for me, as I fill out the survey on what qualities they lack. Smashed bread because some poo kid decided to punch it? 3/10. Completely out of soda for an entire week? 0/10.
I think our local (shitty) walmart is on to this though, they're the only location I know of that not only does not ask about your shopping experience, they don't even print ads on the back of the receipt.
Seriously though, I do not miss receipt check survivalism.