One of the reasons looters need to be shot IMMEDIATELY is that before looting breaks out, only bad people are likely to start it. Once looting breaks out, however, even people who otherwise wouldn't dream of it start to realize that if they don't take whatever they can get as soon as possible it won't be possible for them to get it later.
Once law and order has broken down, it becomes almost impossible to tell good and bad people apart. That's why it's necessary to stop the bad people before the breakdown.
O'Reilly had 2 reporters on that were in the middle of NO after the hurricane and got out. They reported that the looting and chaos started after the prisons were emptied due to the rising waters.
A public service announcement informed them (and the other people in town) that they were going to free all of the inmates and that they (the authorities) could not guarantee anyone's safety.
These were bad people to begin with. And now they are everyone's problem.