I did wonder in another post (not sure if this thread) about putting very slim strips around the edges, even using a paper hole punch to put little dots of the fusible on the back of the applique just to hold it in place.
I'm more than half done with the vines on another 24" center block and it's been no problem at all without fusing. I used pressing bars after sewing them right side out so the seam is underneath. There's no fussing with the raw edge at all, no variation in the smoothness of the appliqued edge because of how much is turned under, etc.