Learned many years ago when my mother was in a nursing home in order to keep her clothing in her room (and in the nursing home) to take black marker and write "Property Of" in large letters on the backside of the dress. Nobody could see it when she was in her wheelchair, and nobody wanted to wear it in public. If you make another quilt, I would suggest writing in large letters about 4" high across the top of the quilt "STOLEN FROM". That way when you bring the quilt home you can applique a wide border (or maybe a hanging sleeve) across that area.