I've done this sort of thing before. I'll start to write something one way, then go back and write it another way, and forget to delete the unneeded words. So the writer probably started with "no camping law" then decided to make it "anti-camping law" but he forgot to delete the "no" resulting in a double negative that means the opposite of what was intended.
It's quite understandable that the writer missed his mistake. That's one reason why newspapers have editors, to catch mistakes before the news is printed. But as I've noted in previous Mental Notes, the Herald doesn't have its own editor anymore, and things like this are slipping through the cracks.
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