Anyway, one time I used safety pins to narrow the sleeves on a jacket I made for myself.
I wore the jacket (part of a skirt suit) in “real life” several times to be sure of the width of the sleeves before making the alteration permanent. The temporary seams with safety pins were so “real” I actually forgot about the temporary alteration and wore the suit multiple times and sent it to the cleaners multiple times. I didn’t realize that until one day I accidentally turned a sleeve inside out when taking off my jacket and saw the safety pins! 🙂