I agree with Bluenoser. This is the same question many of us asked two years ago with the early PlayBook development, and the general consensus was basically that users will become familiar with this feature and gradually come to expect it.
That said, I know some people (non-developers) who've had PlayBooks for quite awhile and they still don't think to check for a top-swipe menu in many apps.
If you think that situation may continue with BB10, you can help them along by doing something like the following. The first few times your app runs, animate the appearance of a small overlay message at the top edge of the screen, noting that there is a menu accessible by swiping down from the top frame. If the user ever access the menu, you could set a flag so you don't remind them again. You could also count, and after 3-4 presentations of such a hint, stop showing it.
RIM may also be looking at some mechanism to make such things more discoverable to users. They already mention it in the user tutorial, but as we all know some users will manage to avoid all such instruction, and still complain that you never told them. ;-)
