> A finger that lingers too long above a spin button may be a guard’s only clue that hackers in St. Petersburg are about to make another score.

Seems like this is easy for the scammers to work around. They could calculate the average time it takes for the scammer to lift his hand from his lap and press the button, and then use that time instead of .25 seconds. Would be less successful, but would seem to be almost impossible to detect.