Earlier quoted context omitted.
Excellent point, though once police departments realize this fact, they may force arrested people to immediately unlock their phones, or use their fingerprints, which they already collect, to do it. It would be nice if you could adjust the 48 hour timeout.
Touch ID doesn't work with copies of fingerprints that police collect. It actually scans the underlying living tissue with RF signals.
(Oops, I was wrong about that. Turns out that was a claim by someone else in the biometrics field, not Apple.)