This is false logic. This way you can only prove that the backdoor exists, not that it doesn't.

What I meant to say was that a reason why it may not be true. I started typing the response with one thing in mind and ended with another.

Point still applies though. No cases where prosecution has cited intercepted VPN traffic.

Ah, but perhaps this is why it's so important gitmo detainees, et al, are not granted a trial?

Not sure about that, but if the FBI were conducting any investigations where they were able to exploit VPN traffic because of a hole in OpenBSD, it would show up in a trial somewhere (and if the prosecution do not present how they got the data, a defense can find out through discovery).