I was listening to NPR the other day and they had this pick-pocket magician. he would rob people blind while doing basic magic tricks in front of them and then at the end show them the damage.
he made an interesting point. he said that if he moved his hands in an exceedingly fast manner, people would always catch him. but if he moved it at a slower speed he always got away with it. also, using just finger tips did not matter, he liked to stick his whole hand in their pockets and do inventories. he said it only required "grift sense" (probably his version of tingjin or whatever ).
[later they had some neuroscientists explain this and how moving in slow arcs is even more effective. something to do with how our brain can't help from analyzing those type of movements etc].
a couple days before that during my private lesson my teacher said that it's very difficult to knock people down with the softness when your hands are moving like the roadrunner. he said if you look at videos of ma yue liang and cheng man ch'ing (his teacher), you can see that is case.