I so wish I had read this thread before my ill-fated Linus challenge quilt! I bought "sky" fabric (with clouds, you know) from my LQS and it just kept growing and growing! Of course, I didn't pre-wash it, which certainly would have helped. By the time I was finished quilting, the fabric was bunched and pinched and totally ugly. Of course it was on a deadline, and it went to a national meeting! I am still embarrassed, even though no one knows it was mine.
Final thought - listen to the kind people on this board and may you never have such a problem!