The thread is about the morality of open carry but has become about the strategy of it too. So just for fun I'll throw in my two cents on both.
Sun Tzu wrote about this question two and a half thousand years ago when he wrote these words: all war is based in deception. And these: Know your enemy and know yourself, and in many battles you will not be defeated.
One who forces you to defend your life against his aggression is your enemy. iIt follows that the less he knows about you the more likely he is to be defeated, which is what you want. This fundamental truth can be played out in a thousand ways. For example, if you carry a pistol in a public place it's unlikely that you will be able to avoid turning your back on someone at some point. Say you are in a grocery store sorting through produce and someone comes up behind you and bashes you over the head with a can of pork and beans. Then he takes your gun and shoots you and everyone around you. If you had been carrying concealed he would have been unlikely to do that because he would not have known you had a gun.
As to the morality part of it, that was also addressed by Sun Tzu, though indirectly. One of the reasons that if you know your enemy and yourself both you will avoid defeat in many battles is that if you know your enemy and yourself you know if you are likely to lose a battle, so you can avoid it or disengage from it (hopefully). And this is the basis of a common argument for open carry: a potential criminal who sees your gun will not do battle against the one with a gun (unless he can creep up behind him and take it). This is the deterrent effect of open carry. The morality of it is that it is supposedly good because it kept a violent incident from taking place.
But as the OP pointed out, the predator who avoids the guy with a gun is likely to just go assault someone else, probably someone who can't defend himself like the guy with the gun could have done. When reading about self defense it's common for a writer to say something like you should [fill in the blank] so the predator leaves you alone and finds a different victim (or go to someone else's house or whatever). That always seemed selfish to me.
It would probably be unethical to deliberately bait a predator to draw him to you (depending on circumstances), but I see no problem with keeping him ignorant of your capability, even if his ignorance is one of the reasons he assaults you instead of the next guy. If the primary reason for carrying concealed is strategic (or tactical as it's called), it doesn't matter if the other reason also exists, because you would carry concealed anyway. So the question is moot.
This opens up a big can of worms in regard to a closely-related question: at what point do you have a moral and legal obligation to let an aggressor know you have a weapon. I put some thoughts together on that awhile back and I'll copy and paste them here, because they address the broader question being raised on this thread:
Displaying a weapon stops a fight from happening far more often than using one, and this is by far the preferred method of self defense among those who commonly carry guns legally. But all rules have exceptions, and there can be times when not displaying a weapon is the better course of action, even if displaying it might avoid a fight, especially if the avoidance seems likely to be temporary.
It has to be up to the defender to make the call on when to display his weapon. His timing and judgment better be good and he better be able to articulate his reasoning no matter what he does, but if mortal combat is being forced on him, it has to be his call when to reveal that he has a weapon. And from a strictly tactical perspective, it’s better for him to keep it hidden as long as he can, so it’s a surprise when he attacks with it. Given the right circumstances, this can be a big deal.
During peacetime weapons are commonly carried concealed by civilians where it's legal. There are various reasons for the concealment but one of the big ones is that the hidden weapon is a big strategic advantage. Those who carry in the open don’t have that advantage. Those who do have to decide when to give it up, to either stop or end an assault.
Drawing a weapon too soon can cause big problems and drawing it too late can too. Drawing it too soon can get you in trouble with the law; drawing it too late can get you killed. How quickly you can access your weapon and use it to terminate an assault is a big consideration.
Unless displaying your weapon scares the aggressor away, the less he knows about you and your capabilities the better it is for you, until you use your weapon and he feels its effect before he sees it, giving you an edge in carrying out a successful counterattack.
If it is reasonably certain that displaying a weapon will stop aggression it’s usually the better course of action. That’s why it’s the most common way for guns to be used in self defense. But a defender is under no moral obligation to give up the advantage of a hidden weapon, if he has good reason to think that keeping his weapon hidden is the more likely way for him to survive the fight that was forced on him.
How this might apply to law has to be determined case by case; there are gray areas and justice is not always part of the law. But it should never be the law that a defender has to give intelligence to an aggressor, if there is a reasonable concern that the intelligence might be used by the aggressor against the defender, even if doing so, as in displaying a weapon, might stop the aggressor from committing his crime, and therefore save his life from what the defender must do to defend herself from him.
Here is an example: say a woman is being attacked by a man in a house and she has a hidden knife he is unaware of. If she gets in close she can use the knife to defend herself by killing him and there is a good chance of success. If she displays the knife, he takes a few steps and picks up a baseball bat or chair and easily overpowers her knife.
Or say you’re surrounded by a socialist mob in a race riot; no guns are visible but some people are getting beat up with sticks and stones and kicked around like you see on the news sometimes. You are escorting some orphans out of the riot zone. You and most of the orphans are the wrong race for the riot but there are white people rioting too along with the colored folks so maybe you and the kids can kind of blend in and sneak out. Maybe you and those with you even carry loot over your shoulder and yell socialist slogans so you can blend in better.
You have a hidden gun and would like to keep it hidden because you want to be as inconspicuous as you can and just get out. If you have to use the gun you do not have enough ammo to shoot your way out of the riot zone, and there is no reason to think the sound of gunfire would draw a police presence (though it might draw an armed criminal presence). Being inconspicuous is a real big deal to you at the moment because drawing attention to yourself could be a very bad thing.
If there is a direct assault against you maybe you can take it out with something other than your hidden gun, like say a hammer or pry bar, both legitimate things to carry as a righteous member of a socialist riot. Do you have a right to use what you carry in your hand as a weapon while you keep your gun hidden, even if showing an assailant you have a gun might have stopped him from assaulting you and the orphans you are trying to escort out of the riot zone? I say you do.
You as a defender are under no moral obligation to make yourself less able to survive a fight by giving up an advantage that might save your life, even if giving up the advantage might keep you from having to kill an aggressor. You have no moral duty to put yourself or other innocent people at greater risk hoping to protect your assailant from the consequences of his own violence; there is no mandate that you give him intelligence he can use to make his attack more likely to succeed, even if the intelligence might save him from the consequences of his act.
If your act is legitimate self defense his death by the weapon in your hand is the fruit of his own hands, and his blood is on those hands, not yours; your hands are clean if it was his own act of aggression that forced you to kill him, even if you deceived him about your capabilities and killed him in a ruthless manner.
Just my thoughts on the matter.
None of this should be taken as legal advice because I’m not a lawyer. The only legal advice I care to give is walk away from a fight if you are able.