Most of the time when this has occurred to me, the original programmer is not around. Regardless, I rewrite the code.

If the programmer is a newbie, I may try to work with them to change their ways.

If not, I don't bother - their bad habits are ingrained, and I've learned by experience that you can't teach a bad dog good tricks. I discuss the issue with my manager. It's best to let managment know that they are a potential problem, and let them deal with it.