Bgt Knife Act

[vernonk]

The guy who threw the knife that pinned Dec’s card to the box round Dec’s neck....how do you think he did it?

[teacher1]

Knife never left his hand ....... trick box. ;o)

[Gizmonster]

I agree with Teacher :)
I don't want to say too much, as I'm not a massive fan of revealing tricks, but does anyone actually think the producers of BGT would let anyone throw a knife at someone, whilst standing a considerable distance away, blindfolded??
I'm almost certain I've worked the trick out, but it's enough to say that the knife never left his hand and the box was gimmicked.