[techdmn]

Well, if somebody walked out on me I guess that would end the interview. :) I have candidates write code on a white board, but not terribly difficult problems, and I always issue this disclaimer:

"My brain doesn't work as well when writing by hand as when I'm typing. This doesn't have to be perfect. If you get stuck, ask for help, we'll talk through it. Think of this as a starting point for a technical conversation."

As a candidate, I would worry about my future coworkers if I were not asked to write code during the interview.

[philparsons]

Indeed, it would be interview terminated.

Perhaps I'm envisaging an ideal world but I'd much rather see some production code they have produced and ask questions about that. It's very easy to gauge someone's knowledge of a particular technology by just talking to them about it.