Personally, I think people throw around the term "Quilt Police" without having any idea what the term means. Now that I have THAT out of the way, I couldn't agree more with Quiltmom04. She has hit the nail on the head.
When I first started quilting I jumped in with both feet. No simple quilts for me. My first quilt was a sampler. It had set in seams, applique, template cutting as well as rotary. It had stars, curves, triangles, diamonds, mitered corners, every imaginable technique. It was then painstakingly hand quilted. This quilt was years in the making. I poured my heart and soul into it and was proud of this quilt. It was made with fabrics from JoAnn's before I knew any better and any different. This quilt took a place of honor on my guest bed where it was gently used. Imagine my horror to see how dreadfully it faded after only a year. How the fabric became threadbare and worn with almost no use after only a handful of washings. My second quilt was a lonestar. Started before quilt one was entirely completed. Also all JoAnn's fabrics. This quilt also was years in the making with 100s of hours of handquilting devoted to it. It also faded horribly but at least the fabric is holding up a bit better. For those of us that don't churn out quilts a mile a minute, that make challenging quilts that take a long time and we hope to end up with an heirloom I will no longer make the mistake of using inferior products. I will also warn new quilters of my horrible experience and let them make their own decision.
Some may call me quilt police when I tell them this tale. I prefer the term "the voice of experience". I will shop JoAnn's for notions, interfacing, specialty fabrics (like ultra suede or Organza) tools and odds and ends but I will not buy their cotton quilting fabric and I quit buying batting there as well (again better deals and better quality can be found elsewhere). I am once bitten twice shy. However, I too, have acquired fabric at thrift stores, Goodwill, yard and estate sales. I am not adverse to using clothing in quilts (Lord knows I have made enough T-shirt quilts!) I am now experienced enough to know quality goods and trusted name brands from manufacturers who, for the most part, will stand behind their product.
Additionally I have found lots and lots of quality fabrics on line at a fraction of what JoAnne's charges without aggravation, without coupons, without using gas (many offer free shipping at a certain $ threshold) and without stress.