what kind of fusable did you use? are your appliques sewn down? the fusables made for quilting projects hold the pieces in place so they can then be sewn into place (like wonder under, steam a seam lite, heat & bond lite)
there are fusables that are (No- Sew) fusables- if you used one of those- you want to let the long armer know so she will not try to sew over them- they are not made to be sewn- and do not soften up- they are best used for craft projects- perhaps wall-hangings- that will not be sewn through- they gum up needles, sometimes break needles- are not meant to be sewn through.
if you used one of the sew(able) fusables the quilter will not have a problem quilting- and the fusable will wash away when the quilt is finished, bound & laundered.