Is it standard procedure to unlatch the cockpit door before an emergency landing in a small aircraft? I was watching an Air Safety Institute video called "Real Pilot Story: Cemetery Crash – A near-death experience with valuable lessons for all pilots." It discusses a situation where a 1958 Bonanza crash landed in cemetery due to an engine failure.

At the 2:23 minute mark they are discussing the lessons learned and the pilot states that "I should’ve reached across and unlatched the entry door because that could jam in a landing, and in a Bonanza it’s very difficult to get out if you jam that door."

Is that really the proper procedure in the case of a crash landing? It seems a little strange to suggest that, while trying to land safely, the pilot should pop the cockpit door open.
As always check your POH for procedures, however most light aircraft call for unlatching the door in the event of an emergency landing or ditching.  Two principle reasons: 1. It aids egress, which can be difficult with a jammed door. 2. It allows better energy absorption of the front part of the fuselage, by permitting it to crumple better.