They have to go to every machine to restock regardless. All they have to do is note down on a little notepad or even an app on their phone what sells, what doesn't and how quick.

I'm sorry, I just can't go along with internet-connected public vending machines. If you want to connect everything in your house to the internet, fine. But a machine that sells candy bars does not need to be connected to the internet just because it's marginally more efficient to do so than the way it had been done previously for decades. Because it results in this sort of shit. And unnecessary price-gouging through selling a university expensive machines with an unnecessary connection to the internet instead of something that worked perfectly well already and didn't cost as much money.