There should also be a timer that puts the phones into require-password mode. So after a few hours they'll need more than a fingerprint.
Maybe you should also have the option of setting up a "coercion fingerprint(s)", which if used to authenticate would put the phone into require-passcode mode. Then, if the court compels you to unlock your phone with your fingerprint, you can put yourself back into 5th amendment territory.
Actually, in that last case, you might already be protected. If 9 if your fingers will force your phone to require a passcode, and only one will unlock it. Could the courts/police force you to disclose which finger is the one that unlocks? I'd imagine you could put them in a situation where they have to chose which finger you use (or manipulate your hand themselves) to perform the unlock action, and in that case they'd only have a 1/10 chance of actually getting what they want.
Maybe you should also have the option of setting up a "coercion fingerprint(s)", which if used to authenticate would put the phone into require-passcode mode. Then, if the court compels you to unlock your phone with your fingerprint, you can put yourself back into 5th amendment territory.
Actually, in that last case, you might already be protected. If 9 if your fingers will force your phone to require a passcode, and only one will unlock it. Could the courts/police force you to disclose which finger is the one that unlocks? I'd imagine you could put them in a situation where they have to chose which finger you use (or manipulate your hand themselves) to perform the unlock action, and in that case they'd only have a 1/10 chance of actually getting what they want.