Re: Officially suggested keyboard interaction for sub-menu items in the "navigation"?

And the spec <http://www.w3.org/WAI/PF/aria-practices/#menu> also said:
"When a menu is open and focus is on a menu item in that open menu, then
Enter or Space invokes that menu action (which may be to open a submenu)."
That obviously can't be applied on "navigation" items because hit Enter key
on a "navigation" item will usually take users to another page.

So, is it improper to involve "menubar" keyboard interactions in
"navigation"?