I do sometimes. The quilt I made for my 5yo DD is backed in minkee, no batting and the one I made for my 10mo DS is backed in fleece, no batting. For DD's, she's a very warm child, she just doesn't need the extra from batting, and for DS's I didn't want to add extra weight so he will be able to drag it around easily when he's a bit older.
I quilted both of them, not tied, but I have tied quilts with batting in them. It just depends on the quilt, who it is for, and what I feel the pattern "calls" for.