I really didn't want to get into this debate, but I will say for someone new to firearms those are definitely "hard rules" and should be taught and followed with no exception. As for someone that has worked in both the Military and LE fields and been an instructor, I would say it's impractical to think you could always follow these rules 100 percent. I definitely always check and know when a weapon is loaded or unloaded. If the gun is unloaded it wouldn't bother me if I flagged my own hand. I'm confident and competent enough in my firearms handling to know how to properly check and clear a weapon.
As for the guy in the picture, IDK. No way to tell if weapon is loaded, or if he even checked it. Seeing the Punisher logo on the backplate doesn't give me a whole lot of confidence.