Take a look at this video - looks pretty good, doesn't it.
Now go back, play it again and stop at the 27 second mark. Do you see anything 'interesting' reflected in the window of the trailer in the background?
Yes, it's a white van with a full tripod-mounted camera rig *pretending* to be the Lumia phone with image stabilisation.
Now, we have no idea if the image stabilisation of the Lumia 920 is as good as the video being shown (it may-well be), but the issue is that there was no attempt to inform viewers that we were being shown stabilisation in the general, not the specific.
Reading between the lines, the more cynical amongst us would translate that statement to something like, "We're very distressed that our expensive simulation of OIS has been outed so publicly and so quickly. We are taking steps to have the responsible marketing people terminated (with extreme prejudice)."
In order to assuage the clamouring mob and as part of their mea culpa, Nokia posted a hastily-shot replacement video; "Here is the video shown at the press conference shot using a Lumia 920. On the right is a Lumia 920 prototype with OIS. On the left is a smartphone without OIS. The difference is apparent."
Unfortunately, not nearly as apparent as the fake video. Furthermore, without knowing the actual location, the differences in colours and saturation between the two videos is rather striking. And potentially not in Nokia's favour.
Memo to the (occasionally) wise: Don't tell porkies on the Internet - you're very likely to be found out.