"If you want to give the candidate a practical programming test (and why not? seems wise to me) why not have him actually write some code on an actual computer, in a normal programming environment?"

I've been arguing for years that if you don't want to code on a whiteboard in an interview, bring your own computer. To every justification as to why that's a bad idea on the interviewee side, my answer is to fix that before you walk in the door, and to every rationalization about why this is a bad idea for the interviewer, I say they're all pretty easy to fix. (You can tell how well someone thinks on a whiteboard, but if you see them use Intellisense you're suddenly clueless about how they operate? Then ask better or more questions.)

After years of being essentially shouted down, I metaphorically throw up my hands at all of you and say, fine. Insist on programming on the whiteboard in an interview.

But stop whining about it.

The power to fix this is in your hands and for some reason you all refuse to take it.