"...one can get around barb wire fences easily on foot..."

Not in the areas I am familiar with, some of those fences seem to run forever. And many go thru ravines etc that are soooo steep I don't know how they put the thing there in the first place.

I have climbed many a barbed wire fence, wearing full uniform (including $150 pants), and never suffered a rip. Most fences, no matter what kind of posts they used, have a much heaver post (almost a RR tie on some) every hundred feet or so, also at corners. Go to that post, put one hand on the top of the post, and one foot on a strand at a comfortable level. Test the wire and its staple by putting some weight on it. Right next to the post it should be almost movement free. Assuming that it is, stand up on that wire, swing your free leg over, place that foot on another strand, test it, swing the first foot over the top, and down you go. Your gear can be tossed over first, lifted over or dragged under after you are over...