Making phone easier to crack

I was walking around the office the other day thinking about the whole iPhone and FBI fiasco going on and a question crossed my mind.  If a phone is locked by a users fingerprint will there still be the same problem when it comes to unlocking the phone after a user passes away?  Could authorities not use the persons finger to unlock it or if they have a record of their fingerprint use a recreation of it on the sensor?  If this is true then wouldn’t having your phone protected by a pin code be better than the convenience of using the fingerprint sensor?  If anyone knows of any research articles about this let me know.