I heard that a quilt arrived at a quilt show with all its markings showing. Apparently the quilt was marked with one of those pens, and was mailed/ travelled in the cold and all the marks re-appeared. The quilter had a note on it asking if someone could please run an iron over it if the markings appeared. The person unwrapping the quilts said we don't have time for that! And the quilt was hung with the markings showing.