They who? Most criminals would wait for a visibly armed citizen to leave before robbing a place.
Do you have statistics that would suggest otherwise?
Where did you get your insight into how criminals think? Are you suggesting that they use common sense?
I've always thought that as open carry becomes more common, things like this are bound to happen. It seems that we are staring to see it now. I recall another story where a devoted open carrier had his firearm stolen off of him while carrying. Open carry has always been an extremely small minority of people who actually carry handguns, in most parts of the nation, and nobody compiles statistics particularly in the category of open carriers being victimized, to my knowledge.
I do, however, know of one statistic that I'm sure of. 100% of open carriers have played their hand if they are ever caught up in a violent situation that they may have avoided if they had not been visibly armed. But each person has the right to lead with their chin, if they so choose. Personally, I prefer to be the gray man.