This is really good. Because I can't count the number of times I would have skipped the bag of pork rinds (311 calories and about 20 grams of fat per 2 oz bag) and instead picked up a healthy Snickers (100 calories and 5 grams of fat per bar) if I'd just known their respective nutritional information.
The problem seems to me that most people who get snacks from vending machines already know they're really bad for you and so they would either not be getting them at all, or getting them anyway because they don't care. So the labels wouldn't do much. And the labels on vending machines that held healthy snacks wouldn't do much good either; the dust of months or even years of non-use would obscure them.