It's 29 degrees Celcius in the shade and thinking is difficult for me! I hate summer... where is the swimming-pool?
Okey, perhaps there is a work-around...
You can create a menu under the main menu, place it hidden and modify the userrights on that menu.
Now the users can create new pages and they will remain hidden.
Once you give approval on a page, you can move it to the new location.