Do new candidates write code during their interview

You probably wouldn't hire someone for a job without seeing if they can perform that job. For instance, would you ever hire a graphic designer without seeing their creative portfolio? Or, would you hire a baker to make your wedding cake without first tasting their samples?

The sentiment should be applied to programmers. Of course, you can still select candidates based on their resumes, references, personalities, or answers to interview questions. However, their ability to write code during the interview should be the most important. After all, that's what they'll be doing all day.