The batting won't hold it, but the quilting might...sort of, if you're lucky. The seams involved will always have more stress than others however. If you block an out-of-square quilt...the same idea as 'stretching' a block...it will only stay square until the next time it gets wet. Then it reverets to it's 'natural' state. It's the main reason I don't force my will on fabrics, preferring to work with them and not against them during construction.