I write my own EAs so I don't know if this is 'normal' practice, but here are my thoughts ...
They may have been able to put copyright on the actual coding, as that is their work, but whether that applies to the idea behind the coding I'm not so sure. Don't think you can copyright an idea, but I'm not an expert by any means.
If that's true then it would only protect the actual code the programmer has written, so you couldn't sell it for example - and as a program can be written in many, many different ways to do the same thing, it wouldn't stop it being written in an alternative way by you, and you'd be free to do what you want with it.
As I say, I'm not an expert on copyright so you'd need further input.
HTH a little bit