In reply to maxbaxter.

for that scenario to happen, you have to reverse engineer the touch id process, get physical access to the phone which belongs to the owner whose fingerprint needs to be stolen with some Mission Impossible or James Bond type stunts, inject that "some software" you wrote, and then you get the finger print as read by Touch ID (it reads the capacitive different between the ridges/nodes, doesn't take an imprint/image).

Now that you have the Touch ID raw output, you are good to use it on .. just the iPhone you injected your awesome software into!

So, until the above stuff happens for real, I'd say, take it easy :)