Well, it may be a vestige from setuptools and I don't know if it's still needed/appropriate, but distribute scans the pyc modules to try to see whether stuff is zip_safe or not when you run `python setup.py bdist_egg`:

https://bitbucket.org/tarek/distribute/src/da2848d34282/setuptools/command/bdist_egg.py#cl-420

Personally, I always set zip_safe to True as I find zipped distributions to be a pain in the butt, but not all distributions out there always set it and currently `python setup.py bdist_egg` (and probably other commands?) bombs on such packages.

We should probably get Tarek to weigh in here.