In my experience, other package managers (my experience is with Python's and Ruby's) will behave just like Haskell's. Specifically, they do not seem to inspect the user's $PATH variable to determine whether their default installation directory is present.
Having used both Haskell's package manager cabal and Python's pip and easy_install. Cabal has a long way to go before it's anything like pip. You can see cabal moving in the right direction, but pip is leagues ahead of it right now, especially when using virtualenv.
