Yes, it is questionable whether the owner is more likely to survive if they draw a weapon. Most armed robberies don't end in someone getting shot: the robber brandishes a firearm, the victim cooperates, the robber runs away. If the owner draws a gun in this situation, they are more likely to be shot, because now the robber has an incentive to fight for their own life...and their gun is already out. OTH, widespread knowledge that the owner is armed may reduce the owner's total number of robberies because at least some robbers will choose to look for easier prey.
I'm not anti-Christian. I'm anti-stupid.