i'm perfectly willing to write code as part of a job interview. just not on a whiteboard or over the phone.
why not on a whiteboard?
Those skills, (being able to code complex problems when people are watching) have never been a requirement of any job I've seen so I've come out of many interviews feeling that they got an inaccurate picture of my skills.
If you try hard enough, you can be familiar with likely interview questions and then the problem is how best to present your solution, which is an important skill, and one worth practicing.
But to solve something say from project Euler on a whiteboard in front of three strangers and talk about my thought process at the same time, that's hard.