Right. If it is a SHTF situation, it is useless unless it's affixed to the top of a fence or something. I can leap and clear a three spool wide, two spool high concertina barrier with gear and rifle at a full run. I'm sure possibly more if I'm desperate enough. That would be a lot of spools to secure a parimeter.
Now, say you have an eight foot-high fence with the wire on top, I'd be hesitant to try. It's also good to have at the base on the interior for the intruder's "safe" landing after scaling the fence.
