From day one, dumba$$es have been saying that, if only a bunch of armed yahoos had been sitting in the theater that they could have shot Holmes before he was able to kill as many victims. Of course, such claims ignore the fact that he THREW TEAR GAS. Without a gas mask, they would apparently be squinting through tears, trying to bust off rounds that would probably hit other movie patrons. Then there is the fact that Holmes was wearing a significant amount of body armor. Some people claim that shots still might have knocked the wind out of him, if they hit in the proper places, but the odds of hitting him properly in a tear gas fogged, darkened theater, amid pandemonium are low enough, and staggering him would probably not be enough. In general, in a gun fight, the guy with the biggest, baddest gun usually wins. Therefore, unless these guys also had AR-15s stuffed in the legs of their pants then Holmes still would have had the upper hand and been able to take out anyone with little pea-shooter trying to plink him through his armor.
Also, we have had concealed carry now for almost three decades in 49 states now, and according to studies such as this one, it has not decreased crime rates by any statistically significant margins. In fact, the only significant effect seems to be to increase the rates of aggravated assaults.
Therefore, it IS time for concealed carry nuts to sit down and shut up.