"Sometimes things that are not true are included in Wikipedia. While at first glance that may appear like a very great problem for Wikipedia, in reality is it not. In fact, it's a good thing." - Wikipedia.
I have read somewhere that barbed-wire was enforced with gunner-mines somethimes even with dummies to hold back the enemy even by thinking that it is too dangerous to trepass. I can not imagine that steel-spikes fitted caltrops will have done a better hold-back effect than " normal " barb-wire.
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Steel can be helpful - you have only to bring it into the "right form "
