Prevention is better than cure...
So the next step would be to warn the developer before they make the code changes or during. Hooking into the IDE to visually indicate hot spots within the source file being edited on would be neat.
Yes, this is exactly right. We didn't have time in the period of an internship to hook into the IDE (along with all the other tasks, like user studies, algorithm design etc etc), so just went with the warning in source control.
Given more time, I absolutely would have done this. Nicolas Lopez at UC Irvine is thinking about putting tools like this at the IDE level, if you're interested.
