The cheeky intern was not cheeky enough to obfuscate his code to make it past the code review and was caught. You can easily obfuscate your code by preparing it in several commits with each commit handling a little part that under the code review inspection of said commit appears not only benign but also necessary to the actual task your implement. And then in one final commit you put everything together and BOOM!, cheekiness implemented, while the manager and code reviewers are none the wise. Or that's how I did it in one such instance ;)