This plugin is not multisite.
When activated network wide, all blogs can still go and change the settings back. Plugin is not hidden from blogs, and cant seem to be hidden.
Also, in the settings, it says:
Deactivate for admin, Deactivate for author, etc...
But it does not really deactivate anything. It only removes the menu from the site. Anyone who knows the links of these buttons, can access any plugin, menu, setting, if they know the link.