> What is intolerable is having a 3rd party hold your entire product line hostage, based on some issue with an unrelated product.
That seems like an irrational fear, I can't imagine the copyright owner getting an injunction against or even pursuing code that you can trivially show the provenance and licensing for. The issue is that, for an organization that is ignorantly shipping code in violation of copyright, the problem is likely not just one software on one product but probably all software on all products and instituting comprehensive license compliance is the simple and efficient option.
Would it be any different if the problem was, for example, the copying of images off of websites for product art rather than properly licensing images from iStockphoto. Just because you can download something off the Internet doesn't mean you can ignore copyright, which is a common misconception for many businesses.