I think this is a clever trick that is great for a sleeveless vanish.
My only issue is
that the second 'coin' should be a 'normal' coin (front/back heads/tails). In this case, it is an
extra gaffed coin - one side is black. When you do a plant for after the vanish, that coin has a
black side...no reason to point them in the right direction. A normal double-sided coin would do the
trick. :)