I've worked in the restaurant business for almost 20 years, and we (the servers, managers, wine directors) have always referred to that tool as a 'wine key.' A 'corkscrew' was the old-fashioned rabbit-eared device for home use, too bulky to carry and use at a table...the 'wine key' was the waiter's tool. It's definitely not a marketing tool, and it's definitely not expensive, it's just convenient :-) Interesting read though!