I've written some interview questions before and can confirm that having people find and fix simple issues in code is a surprisingly great way to weed out people who have no clue what they're doing.

> Cheating effectively is indistinguishable from debugging skill. Even with knowledge of the exact bug ahead of time, if you just open the file with the bug, barf out the code to fix it, and run the tests, you’re going to fail the interview.

Did you mean "distinguishable" here, by chance? The first sentence seems to contradict the second.