If you get really good at this sort of thing you can take people's wallets just by asking
http://www.youtube.com/watch?v=DR4y5iX4uRY
Part of the trick is that during a routine operation - like a handshake - or asking for directions - you're brain drops down a level of awareness - you are basically on auto-pilot - but the illusionist interrupts the operation, you're still stuck in sub-optimal awareness pattern, and then you get manipulated in some fashion.
If you liked that one, this one cracks me up everytime, http://www.youtube.com/watch?v=UdlItEIj8bg
I don't know to what degree that actually works, but it's pretty interesting.
See what happens when you leave a wallet on the ground: http://www.youtube.com/watch?v=bxYCh_p2Mjs