On-the-spot writing test during a job interview?

[Keith Cronin <kcronin -at- daleen -dot- com>]

I have been asked to be one of several people who will each individually
interview the same applicant for a copy writing job at a software developer.
I'm the company's proposal writer, and have previously worked as a technical
writer for this company. The company is looking to me to help judge the
applicant's "writing skills and creativity."

What do you think of giving the applicant a writing test during the job
interview? 

I had to take such a test for a previous tech writing job, cranking out a
description of how to use a stapler, assuming no "stapling knowledge" on the
reader's part. 

The job in question here is a marketing-oriented copy writing job, NOT a
tech writing job, but the applicant IS expected to be able to write about
high-tech and/or abstract subject matter.

I thought it would be a good idea to administer something along the lines of
"the stapler test," but a well-respected colleague has suggested that for
people who "don't test well," it would apply unfair pressure (in addition to
the pressure inherent to any job interview), and could produce deceptive
and/or potentially damning results. 

I tend to feel that EVERY pro writing job is a test of one's ability to
write under pressure; for me such a test was a chance to "put my word
processor where my mouth was." But I don't want to be unnecessarily harsh on
a job seeker.

What do YOU (fellow TECHWR-L members) think? Thank you for your input!

-Keith