A fellow I know got his first kilt some time back, and was baffled by the basting stitches as well. He wore his kilt out the first time with the stitches still in, and got all upset about the terrible fit, etc., until I was able to set him straight.

It would be the simplest thing in the world for kilt-makers to enclose a little card with each kilt shipped, explaining the dang basting stitches...!