An "add space" link may appear if the Confluence instance retains the default content with the four "Get started" steps.

If a user without create space permission clicks this link, they will get presented with the "Add Space" dialog. They will then take the trouble of creating a valid space name only to find that they do not have permission to perform this action.

The Create Space dialog should not appear in the first place for these users. The "No permission" page should be thrown when the user clicks on the rogue link.