OK, but a little predictable...
Well, the trick works - but being presented online (rather than in person with appropriate misdirection) makes it a bit easy to see how it's being done. To the reviewer(s) below who claim it doesn't work at all, you've not read the instructions properly - if you do it right, there's only one possible place you can end up no matter what number you start on (and by the time numbers start being removed your position is already known).
I think this could work a bit better if the presentation was made more slick and distracting (without being over the top) to make it less obvious what was going on... still, it's one I'll have to go and try out IRL on someone :)