tl;dr: Ross was a colossal idiot who ignored warnings about the shoddy state of his opsec. I hate to say it, because Ross and I have a few mutual friends, but the guy was an idiot, and it's looking more and more like he deserved what he got for being so utterly stupid .
Calling him stupid seems to kinda miss the point to me. I think it's more that when you're up against the Feds, especially on something so deeply entrenched as being illegal worldwide as distributing drugs on a massive scale, you're going to get caught eventually, because it only takes one mistake. Sure, he was kinda dumb and made a lot more than one mistake, but how much better could anybody here do? Enough to keep…
Well, Kim Dotcom is still kicking it.
As for Ross, the evidence might have been circumstantial at best if his un-encrypted notebook wasn't grabbed.