I would also add that doing a physical contact check of the chamber with your pinky or other finger is an important technique to use, every time, regardless of lighting conditions. The point is to train yourself through repetition to always do it, every time. The reason for this is there may be times where you need to clear a weapon, or even just check to see if it is loaded/unloaded in low light conditions. I realize it may look odd doing it in a well lit environment, but again, it's just a matter of simplicity and repetition to do it the same way every single time. It's always the last thing I do in my check, after the visual inspection once the firearm has been cleared and the action locked open.
Also, all of the major 4 safety regs play their part in safety. Checking to ensure a firearm is unloaded before handling it in a non shooting environment/situation IS important, but equally important is muzzle control discipline as well as finger off the trigger and pressed with some reasonable force above and outside the trigger guard. I see many, many, many cases on the net, on TV shooting shows, and at the range, where people clear their firearms, then proceed to sweep everything and everyone in sight with the muzzle, and the same goes with the ol buggar picker on the trigger. I can usually tell if somebody is professional and trustworthy around firearms within a few seconds of observing the way they move with them, particularly when unloading/checking and then doing some sort of demonstration directly afterwards. If they move the firearm's muzzle around other people and their own bodies, always keeping it pointed in a place where it wouldn't harm any human or launch rounds far downrange out of sight, as well as keeping good fire control finger discipline - I then will relax, at least a little, and listen to what they're saying/teaching as opposed to cringing then opening my yap to tell them they are being unsafe.
