These demos are ALWAYS "scripted". At one point, the "uke" seems to be lifting her up.
A nice bit of tumbling, but as a effective grappling/take down move? I'm skeptical.
I am too. Some commenters over at reddit stated they watched this as it happened and that this was legit. One stated was that with this particular move, if the person being taken down resisted, they'd have their neck snapped.
Still - even with all of that said, it does look scripted.