It would be really nice if we could override the global enhanced notebook security setting, or better yet have global admins toggle whether the global setting can be overridden, on a per product or per notebook level.
I've got some products that are internal and under no circumstances do I want the notebooks being shared externally. I've got other products that are much more collaborative and I'm fine with publishing a link on a web page to the notebook.
At the moment I can't achieve both results.
We currently have many layers of security which are available on Notebooks.
As you mentioned, there is a global setting to indicate whether notebooks can be viewed by everyone (or only Aha! users).
However, for each Notebook, there is also the option to add password protection for the specific notebook. On the notebook detail page, you can access this through the settings button.