I think there is a time and place for this. I've had cops do as you advocate, as well as cops who said "You leave yours alone and I'll leave mine alone, sound good?"When I was a cop and made a traffic stop and the person said they had a gun I all ways took the gun with me while I wrote the traffic ticket. I verified they had a gun permit and all ways gave the gun back unloaded and asked them to load it once I left. It is lawful for an officer to do this for his safety.
Guess which approach I respected more?