Does anybody know it or happen to have a video showing it? I want one incase I ever go to an apple store and all the iPad's are taken? Also would it work on my own iPad?
You're talking about interfering with signage at a store. Think about it in the lines of spray painting on a store's poster. By going into an Apple Store and using whatever "secret gesture" you can to convert their smart sign to a regular ol' iPad, you are quite literally interfering with their product advertisement. At the very least, they could call the police on you for vandalism. Whether that charge sticks or is valid is a wholly different topic and would be highly dependent on your location.
If they catch you messing with their signs in a way that the signs aren't meant to be messed with, they can also kick you out of the store. Trespassing charges follow that if you decide not to leave or ever come back without prior permission.