When Elsie stitches a pleat, she pins once at the waist, uses the needle as a pin to hold the bottom of the fell, and then puts some tension on the pleat and stitches without any more pins and with no basting. She's quite adamant about this being the right way and will rap your knuckles if you try to add pins. The rationale is that time is money, and a professional kiltmaker needs to be speedy.
Indeed, time is money! For all industries. I learned to sew exactly the same way using my sewing machine. Factory sewing methods were introduced into the home sewing market about 15yrs ago. Sewing most seams you would anchor the top end at the presser foot, match the very end and hold in your right hand, then fold up the seam into your right hand, then keeping tension on the seam using your right hand, start sewing, using your left hand underneath the top layer helping the seams to match as it goes under the presser foot. I've seen people set in sleeves using this method. I'm not there unless I'm working with wool. The cotton velvet of the dance jackets? Ick.