I suspect that if one can copy the product, they can just as easily copy the packaging. And therefore, "Certificates of Authenticity", purple silk bags, beautifully painted wood crates, etc., don't guarantee much either.
My experience with cables parallels those of Newbee. There are some cables that truly have that wow factor and affect the tonality greatly. The one that comes to mind is the Cardas Golden Cross. This has a warmth that is very lush and works well as a tone control for a system that has a little bit of a brightness character. I found the Straightwire Virtuoso to be exactly the opposite. Once I got my system to be more neutral, and I removed the Cardas and SW for the MIT and NBS, everything was much more in balance.
Several years later with the MIT & NBS, they still both work so very well with my upgraded system. Even between the top MIT and NBS in my system, there are subtle differences of a little more resolution vs. midrange presence. But overall the swap between these two retains the sonic character of the system. Either they are both doing something very "right" or they have exactly the same flaws to not allow me to hear what a "better" cable would do. I simply don't think about it any more.
When you get your system to a point where cables of such different engineering implementations make very little difference, you can quit worrying about cables altogether.
John
