Ask your potential programmers what name they want for their account. If they say their last name is fine, forget it. Another way to sort the goats from the sheep is to offer a choice of company credit cards. Business management types always fall for the VISA card. Real programmers want an MCI card so they can cut the cost of hacking at home.
Real programmers know where to buy junk food at all hours.
Bear in mind that some real programmers are health food freaks. Ask discreet questions about diet. Today, this is not necessarily true. Never hire anyone who likes fourth generation languages. Real programmers play video games.