Have you ever heard of someone bringing suit against someone for something they can't prove occurred? Your answer should be YES because you have heard of these cases. I still say they cannot "prove" (without forum posts and reseller panel channels viewed) that any circumvention took place. They can "guess" and they can make a "hypothesis" but that's not what a law is based on (at least its not supposed to be). Its based on "proof", and YES I realize they only have to prove 51% but its still guess work on their part. There is no logical way to prove that any circumvention took place based solely on a purchase of some codes.
That would be like me and you exchanging some PM's about you buying a login to a site. I sell you the login and maybe you don't use it (because you decided not to), maybe you c/p it wrong and it doesn't work, maybe it was for a buddy of yours, maybe the pass got changed before you could use it. Bottom line though without any record of you actually logging into that site I sold you what evidence exists that you did in fact log into it? None whatsoever. Now as an attorney looking to reap benefits from a lawsuit can I "guess" that you used the login? Of course I can. Can I make a "hypothesis" that you used the login? Of course I can. But regardless of all the guess work there is no "proof" that you did in fact use that login.
The same logic can be applied here.
Preponderance of the evidence is a scam IMO as I could allege any wrong doing I wanted against anyone by simply shifting the facts and outright misstating the facts. DN/Nagra is doing exactly that here by stating unequivocally that someone "used" a code when in fact that person may not have used that code at all.