Cables-how can you be sure of authenticity?

I hope I don't step on anybody's toes with this post however I was just wondering if it is possible to copy expensive cables accurately and pass them off as originals?

I had an experience with a good friend who bought a very high ranked interconnect without packaging-it looked very good and whilst it sounded good we were not blown away with it's performance and I must say I've always had a doubt as to if it was the real thing.

Does this type of thing go on or do some sellers just have access to a good supply of highly rated cables without packaging?