Yes, I would have also thought that since this was a presentation to the general consumer and not just a tech demo ala WWDC where these things don't matter yet,

Yes, I would have also thought that since this was a presentation to the general consumer and not just a tech demo ala WWDC where these things don't matter yet, that they would have addressed this issue by showing a person taking the watch from one wrist and putting it on the other and thus showing the device can be turned around and used just like before.