I do the same to people who refuse to follow specifications they agreed to follow.

There is a slight satisfaction to get back at them for continually delivering much lower quality than is required.

But it really is to cover me. Because, it always happens, later in the future that edge case comes up, and everything breaks. And management is ready to blame me. But then I show them that I tested the edge case before the conclusion of the project. And that programmer ignored my emails, and that I told management these edge cases weren’t covered. But then management signed off on calling it complete. And suddenly management is no longer red with fury. And they usually won’t allow me time to fix it. So the can gets kicked down the road until the next time that edge case fails.