What I hear in your comment is that if you want to steal people's fingerprints, you'd have to target-advertise them a clone of fruit ninja, possibly designed so that certain specific angles of fingers are clearly optimal for doing well at the game.
Most people use their forefinger or a thumb to swipe, and their thumbs to match/type, and multiple fingers or both thumbs to scroll/zoom.
More interesting is that if one had full knowledge of a persons prints then perhaps with microphone, touch tracing, and wide angle video, one could compare expected vs measured sounds. This is a one-one confirmation rather than one-many match. Perhaps it could prevent long term usage after a person had unlocked their device and another was using it.