rubber cement stays (pliable) that is probably why she has chosen it for her (tool of choice) some of the glues when dry become very stiff- even crack- so the rubber cement would remedy that. the fumes disipate quickly- and any residue would simply wash away when the quilt is quilted.
i like using rubber cement for different applications in my sewing room because it remains so pliable-for ever- never gets stiff-or cracks/breaks