This is a somewhat subjective quesiton but I'd love to hear feedback/opinions from either interviewers/interviewees on the topic.

We split our technical interview into 4 parts. Write Code, Read & Analyse Code, Design Session & Code on the white board.

For the last part what we ask interviewees to do is write a small code snippet (4-5 lines) on the whiteboard and explain as they go through it. Let me be clear the purpose is not to catch people out. We're not looking for perfect syntax. Hell it can even be pseudo-code. but the point is to give them a very simple problem and see if their brain can communicate the solution to us. By simple problems I mean "Reverse a string", "FizzBuzz" etc...

Note that we always ask for an explicit language first. We're a .NET C# house. we've only said "pseudo-code" where someone has been blanking/really struggling with the code.

My question is "Is it inappropriate / unreasonable to expect a programmer to write a code snippet on a whiteboard during an interview ?"

In my view, It is very appropriate.  If you are wanting a job to do a particular skill, then it is entirely appropriate to be expected to demonstrate that skill at interview.

The effect of this technique on the recruitment process is very noticeable. 90% of candidates fail this task.  but the developers recruited are good, and the developers will be respected inside the company.

If as a candidate facing this technique, first of all relax.  Its about assessing you as a programmer and your thought processes.  It is not about your perfect syntax.  If you make a syntax error then I might play the role of a compiler and tell you that the code fails to compile on a certain line, and give you an error message, and see how you respond.  Likewise if you add a ;  onto a loop or an if statement that would compile, I'd play the debugger and talk you through a single step through the code.  Again, its not about the mistake, its about how you would cope with the mistake, and are your thought processes good.
