For the most part I agree with you. But, if a programmer has to be the one responsible for a piece of code, then in a manner of speaking, that programmer owns the code, or at least the responsibility. Responsibility is a pricey word in a company, seeing as so few are actually willing to accept it. Either way, whoever is originally responsible for the code should know whenever someone else lays hands on it. Either by written message or through some kind of source control setup.

A coder who changes someone elses code does not have to document every change, but the previous author should at least be notified that there are changes. That takes all of what, 3 minutes via email...."Hey I changed some stuff in your program, and consiquently broke it."

I would think there is also a failing on the part of the supervisor who doesn't notify the original programmer that things have changed. Flat out, the whole deal is a communications failure in this fellows work environment. Unless of course this fellow didn't read his mail first thing? But I doubt that ;)