I've the problem that a restriction to write access only for pages (not posts) fails. It is the same situation as already described in post How to Allow specific group write access to page? and it seems to be a software problem.
Write restriction to posts (via category) works but write restriction to pages with read access to all seems to fail.
I've a board of editiors with cabability 'edit_other_pages'. But some pages are only used by plugins and should not be accidently be modified. Thus I created a UAM group 'System' and added no role and no user to it. Pages with only the group 'System' checked in the 'Access' widget should now be changeable by users with administrator rights only.
This fails. The editors still have write access to the page and can save their modifications.