An automated pot-selling machine was unveiled at an event held at an Avon, Colo., restaurant Saturday, promising a potential new era of selling marijuana and pot-infused snacks from vending machines directly to customers. Its creators say the machine, called the ZaZZZ, uses biometrics to verify a customer's age. The machine is climate-controlled to keep its product fresh. You may be picturing a vending machine on a sidewalk, ready to dispense pot brownies to anyone with correct change. That's not quite what backers of the machine have in mind. For now, at least, the ZaZZZ is aimed for use only by...