Open carrier the first one to be shot?

One of the common criticisms of open-carry is that having a gun on your hip will result in an increased chance of you being the first person killed during a robbery/etc. The scenario is played out as follows: Crazed gunman runs into Starbucks, sees you with a gun on your hip, and says to himself, "That guy's armed. He's a threat. I better shoot that guy first." *BANG* Then he goes on to rob the place and/or shoot everyone else.

I've recently come across a good counterpoint to that criticism:

First One To Be Shot:
There are some who criticize open carry and claim it will make you more of a target or ‘the first one shot’ when a robber walks into the 7-11, despite the absolute lack of credible evidence that this has ever happened.

[...]

Robbing is an inherently apprehensive occupation, and one that doesn’t respond well to instant modifications. He is not prepared to commit murder when he only planned for larceny. He knows that a petty robbery will not garner the intense police manhunt a murder would. He doesn’t know if you’re an armed citizen or a police officer and isn’t going to take the time to figure it out. Either way, if someone in the 7-11 is unexpectedly armed, how many others might be similarly adorned and where might they be? Does this armed individual have a partner who is likewise armed behind him in the parking lot, someone who is watching right now? Self preservation compels him to abort the plan for one that is less risky. So we see that the logic matches the history; open carriers are not the first ones shot because it doesn’t make any sense that they would be.

And if you look at the anecdotal evidence, the author is right.