No way! If it's done, and I didn't see the mistake, the last thing I want is for someone to point out an unfixable error. I posted a quilt on here recently, and someone pointed out a mistake - which I had missed in all my views of the quilt. Fortunately, it was fixable because I hadn't quilted it yet - and once it was pointed out I couldn't leave it. But if it was already quilted, that would have spoiled my enjoyment of a quilt I loved when I made it. I say bite your tongue, especially if the quilt is past the "easy to fix" stage.