Ironically, this looks like another excellent argument against the use of fingerprint authentication. It makes it easier to capture someone's fingerprints without their consent - "Hey, could you hold my phone for a sec?" - "Thanks!"

Oh, and it is easy enough to break TouchID[1], so what makes using the smartphone camera any more sensible?

[1]: https://www.ccc.de/en/updates/2013/ccc-breaks-apple-touchid