"Well, I wasn't addressing the issue of two-legged predators so if you have to worry about them, the rules change.”

No, actually the rules do not change, because there are no rules. There is simply the fact that I do not go into the woods without a visible firearm. (Let me point out I’m not talking about the local state campground here.)

“A human predator is either going to be deterred by the fact that you're carrying a firearm, or is going to try to take you by surprise.”

I think it is far more likely that a human predator will pass on an armed potential victim in favor of someone…..well, to be blunt, someone like you ( i.e.: not visibly armed).

“Either way, whether the gun has a live round in the chamber is likely to be irrelevant, unless you're aware of the predator's presence and have taken precautions. (Cops don't usually patrol with a loaded gun in their hands; they only draw their weapons when responding to a call, and not always even then…)”
“As far as shooting the squirrel goes, I would question whether the .5 or so seconds saved by having a live round in the chamber would counterbalance the inconvenience of picking #9 shot out of my kneecap should something go wrong .....”

I appreciate the fact that you do not hunt, and you have honestly and courageously admitted your lack of knowledge about firearms. I have grown up around guns and have hunted all my life, and I still consider myself very much an amateur. But your remark about a “live round in the chamber” being irrelevant is simply wrong; Revolver, semi-auto, bolt action, or pump—all can be brought into action MUCH faster with one in the pipe, and, at least in the case of a modern double-action revolver, just as safely.
And cops in Israel DO patrol with loaded guns in their hands; I guess it all depends on the general threat level, doesn’t it?

“I'm personally far more worried about some colour-blind yahoo who thinks I'm a bright pink moose wearing eyeglasses than I am about someone who wants to steal my wallet and backpack.”
"I have no control over whether someone else is an idiot or not; the best I can hope to do is avoid being in the woods with them. "

Stereotypes aside, I’m personally far more worried about the gent who mistakes his gas pedal for his brake when I am in the crosswalk. Idiots, yahoos, morons, and thugs are all more likely to get you in the city than in the woods. The threat is there, I know, but the fact remains that hunting is statistically far safer than most other forms of recreation. I respect the fact that you do not hunt but I would urge you not to let your fear stop you from enjoying a beautiful fall day in the woods.

“Polar bears, of course, would be a different matter again, as they apparently do consider humans to be a legitimate food source.”

As do, apparently, some black bears around here (Utah). A few years back one came into a campground at night and dragged a five-year old girl out of her family’s camper. IIRC, her grandfather chased it down beating it with a maglite until it released her. She lived but was terribly scarred. I still consider bears to be at most a minor threat.

Regards, Vince