I was really hoping this thread would die on its own, or remain a joke. Since I am in the vending business, let me say please don't do this.

Outside of soda machines owned and operated by Coke and Pepsi, most vending operators are the smallest of small business. Beyond the cost of the hardware, data/cellular fees run $10+/machine/month. Transaction fees (because transaction values are so small) run 5%+ and your refund will cost the operator that transaction fee. And that's all before you run the coin mech dry and the machine shuts down and sits making no money until someone fixes the problem. This is just not something where you can argue no one is getting hurt, or only a big bank is getting hurt.