Great point! The value of an life is much and much higher than the value of the information on some one's phone. But not putting a code one your phone isn't the solution. We should start with telling people that even when a phone is locked it is possible to call the authorities! In the lock screen of an iPhone you can chose to make an emergency call.
With an iPhone you can even enable an extra emergency feature. This enable any one to contact a emergency contact of your choosing. What this also does is provide the first responder with some critical information like your allergies and blood type. When you don't have an code on your phone it could be an hassle to get this information. But still people doe have to enable this feature on there iPhone.
I'm not sure if this emergency feature is available for android to be honest.
Still you make a good point and everyone need to think about this. What would you do in a emergency situation and what do you want others to do?