If the project is in the design stage and can be fairly easily repaired, then a PM is appropriate. Never should you point out a perceived flaw in an open forum. If someone asks for opinions and assistance, then they have opened the door for you to offer your opinion, but it should be done in a constructive and helpful way. If the project is completed and the flaw cannot be fixed, then no, nothing should be said. I would assume that anyone posting a finished project/quilt on this forum is looking for a little affirmation that they've done a good job. They are not looking for criticism. At least I'm not looking for criticism as a beginning quilter. Believe me, I see many flaws when I critique my own work and I am learning which areas I need help with. I will ask for help when needed.