The capability of manufacturing should be discussed during the design stage so that the designers know that their choices will allow it to be made. Additionally, it is rather naive to believe that something either passes QC or does not. Having more than a 4 decades of employment in manufacturing I can tell you that just because something does not meet specs is no assurance that it will not ship. Besides that taking items that are not in spec and reworking them so that they are is less likely to be as good as making them right in the first place and is certain to lower profit.