often (especially for shop samples) fused applique is not stitched down-0n wall hangings- they just figure it will never get washed and doesn't matter-
unless you are making a sample-
even with fused applique the pieces should be stitched down- it is still raw edge applique (which simply means the edges are not turned under- but yes they should be stitched- with time humidity can cause the fusable to let go- if you don't stitch it down your pieces could start falling off.