I wouldn't count on the "come work for us" being a planned goal of the evening - it's just that those companies are always on the hunt for new hires and take any opportunity they can to connect with good people.

The same thing happened at SydStart the other day - lots of great and inspirational speakers but all of them that were involved with large companies (BigCommerce, Freelancer.com etc.) had a "we're hiring" at the end of their talk.