Working in my virtual environment, any import calls not resolved in the virtual env will be resolved in the "original" environment is possible. At the same time, according to https://docs.python.org/3/tutorial/modules.html#intra-package-references , relative references are allowed. I worry this could lead to confusion/conflicts with different versions of the same named objects entering or trying to enter a programs execution. I am a novice to Python, and I am sure this issue is covered in documentation, but I can't find it. Any pointers?
Update 5/13/2017 - I found the following documention for python 3.6.1: https://docs.python.org/3/library/venv.html#creating-virtual-environments
On Windows, invoke the venv command as follows:
c:\>c:\Python35\python -m venv c:\path\to\myenv
usage: venv [-h] [--system-site-packages] [--symlinks | --copies] [--clear] [--upgrade] [--without-pip] ENV_DIR [ENV_DIR ...]
--system-site-packages: Give the virtual environment access to the system site-packages dir.
The default is not to have access to the system site-packages directory. Therefore I surmise that any code outside of the system site-packages directory is considered "safe enough" with respect to usage of relative import paths, and the user is responsible for not colliding with those items.