use it as a question only as long as you expect the candidate to tell you his thought processes as he describes what he thinks should be happening. Who cares about the right and wrongness of actual code in question - in the real world, the candidate would find code like this, find it not working and debug it with a combination of debugger and writeline calls, so its a useless question if you want candidates who know (or guess) the right answer.
But those who can explain what they think would happen, that's a different matter. Hire them even if they get it wrong.
