Let me try to clear some things up..
California law allows open carry on an unloaded firearm, and it allows you to carry a loaded magazine. The mag just can't be in the gun. It takes approx 2 seconds to draw, insert the magazine, rack a round. Not the ideal solution, but it's better than having nothing when the chips are down.
The movement in Cali of people open carrying is part protection, but moreso to change the culture. It's to get the general public to see that guns are not evil, that guns in the hands of law abiding responsible citizens do not just go off, and that they are nothing to be afraid of. They are trying to change the law and the perception to change California into a "shall issue" state.
Many Cali police are not entirely familiar with the new open carry laws, and there were many incidents in the last few months with officers who did not know the exact law who became very confrontational with open carry citizens. Then again, some of those carriers also instigated, claiming "their rights!! their rights!!" instead of being polite and cooperative to help build trust and improve that officer's knowledge.
Since those incidents, many Cali departments have been instructing their officers on how to interact with an open carry, what they can and can't do, what they should do, and so forth. So to see an officer do it right is refreshing. It's a sign of progress in the responsible gun ownership/carry movement.
The police are allowed to stop an open carry and inspect the firearm to make sure it isn't stolen, it is legally owned, it is unloaded, and so forth. When doing so, it is recommended that individuals allow the officer to manipulate the firearm the ENTIRE time, from pulling it out to putting it back. The key words here are "polite and cooperative."
If the firearm is unique or requires extra safety precautions, the individual should instruct the officer verbally prior to starting. This protects everybody. But then again, you're only allowed to carry it unloaded... so if it goes off in the officer's hands, you were already breaking the law.
If another cop who wasn't involved or was far away or who just came on the stop saw you drawing a pistol in front of a fellow cop, there's a good chance you'd get shot. Let the officer doing the stop do his thing, keep your hands open and in plain sight, don't make any sudden moves and be respectful. Many of them also carry a copy of the state law.