Actually, in the very early 20th century, I would make the argument that pleating to the sett was not all that common. Apparently it was just starting to come into vogue. In 1901, Ruaraidh Stuart Erskine wrote in The Kilt and How to Wear it about a recent novel form of pleating, the name of which he did not know, but he described it as "revealing the whole tartan pattern." He speaks of it as a very new thing, just starting to come into fashion.