I am using Evernote Pro, and I've also created a Free account with a different email address to test the functionality of sharing.
I shared a notebook from the Pro account to the Free account, and lots of personal tags that don't exist in the shared notebook are showing up. If I click on one of the tags, no notes show up --- of course, since no notes in the shared notebook have the tag. This would be horrible if I were to share a notebook with a client.
On top of that, when I try to "Leave" the shared notebook from the Free account, it says I have left, but it doesn't remove the notebook OR the notes (OR the tags of course)!