I've been on the other side of such requests before.

First consider why people ask for code samples. The problem is that it is easy to inflate resumes, and it is very hard to get a sense of how good someone is in an interview. Asking people to code under pressure causes many to do very poorly. A code sample (as long as you are pretty sure that it really is that person's sample) gives a coder a good sense of what it will be like to work with that person's code. The sample doesn't have to be long, a page or 2 is enough. It also doesn't have to work. You're planning to read it, not run it.

Then why doesn't everyone ask for them? Well if you don't have actual coders involved in making the decision, it is a useless piece of information. Furthermore there are candidates who legitimately can't provide you with a sample. And more who will refuse you. It is a lot of hassle to ask for it.

However if you do have coders with an active role in making the decision, in the current market there isn't any reason to give slack. After all available candidates aren't lacking. And experience suggests that most candidates who actively don't want you to see their code have reasons for that - reasons that would make you not want to hire them. The remaining good candidates who just don't have code because it belongs to a previous employer, well if you can't manage to create some new code on demand, then how will you create it once you are employed?

OK, that is unfair to people who need a development environment to work in and don't have it at home. This is a real problem for, say, mainframe folks. But with PCs, my expectation is that motivated applicants should be able to find a way to make it work.

So if I ask for a code sample, and the person can't or won't produce one in a reasonable time frame, I'd remove that person from the list of candidates and move on.

Besides, odds are that someone who is motivated enough to play with stuff on their own time is likely to be better than someone who isn't. And someone who plays with stuff on their own time won't have any problem producing code to show you.

Conversely if any of you are on the other side of a hiring decision, I'd strongly recommend asking for code samples. I think that you'll find them surprisingly interesting reading material.

Cheers,
Ben