Not everybody who approaches the machine or walks past it is really consenting to their appearance being logged and analysed though - not to mention that "we don't store data" is only true if the security is effective and no exploits manage to weaponise the camera now staring back at you as you try to make a purchase.

Ultimately vending machines are completely passive sales anyway, the collection of demographic data about who is buying from the machine are a little useless because it's not like the machine can work on its closing techniques for coin based candy sales.