The purpose of "cloning" is to share the license between the VMC account and the Extender account on the same PC. One limitiation in cloning, so far, is that you can only have the movie player setup (initialized) to run on one account at a time - therefore, if you initialize the player on the VMC PC and play a movie, when you go back to the Extender you will need to re-initialize the player to work on the Extender. This essentially transfers the license to the Extender - cloning will not allow you to play a movie on both the VMC account and the Extender account at the same time.
If you want to play a movie on the Extender and, at the same time play a movie on the VMC PC, you will need to use up another license (i.e. don't clone).
It's always possible that Netflix could change the player to prevent this from happening, but it seems to work right now.
- EricL