When I easy_install some python modules, warnings such as:
<some module>: module references __file__
<some module>: module references __path__
<some module>: module MAY be using inspect.trace
<some module>: module MAY be using inspect.getsourcefile
sometimes get emitted.
Where (what package / source file) do these messages come from? Why is referencing __file__ or __path__ considered a bad thing?
easy_install doesn't like use of __file__ and __path__ not so much because they're dangerous, but because packages that use them almost always fail to run out of zipped eggs. easy_install is warning because it'll install "less efficiently" into an unzipped directory instead of a zipped egg. In practice, I'm usually glad when the zip_safe check fails, because then if I need to dive into the source of a module it's a ton easier.
I wouldn't worry about it. As durin42 notes, this just means that setuptools won't zip the egg when it puts it into site packages. If you don't want to see these messages, I believe you can just use the -Z flag to easy_install. That will make it always unzip the egg.
I recommend using pip. It gives you a lot less unnecessary output to deal with.