If you need that kind of information, you have to use the Package->subroutine() syntax (at least I think so). Then the package name is passed as the first argument, just like the object is in method calls.
Comment on Re: Identify the package a subroutine is being called from
Well, I am adding code onto an existing module, and I cannot guarantee thats how they call the subroutine. It is driving me nuts because of it too! Otherwise that would have been the easy way to fix it.