if the item will be laundered it is important to follow the quilting guidelines- if it will not be laundered it will not matter- many people making wall hangings do not bother with batting unless they need the (loft) to help show quilting detail. often just a layer of muslin or flannel is enough.
any project that will be laundered needs to be quilted to the recommendations on the batting if you want it to last. you can buy batting that allows up to 10" between quilting lines.
if you choose to use the batting you have and not quilt to specifications you should probably add to the label that the item is not washable- so someday down the road someone does not toss it into a washer- without knowing better