I don't think privacy defense going to work well in his case.
Even if it doesn't stick its highly likely that because of this the prosecutors will have to share the big secret - how they got access to the Silk Road servers.
They've been keeping that a BIG secret up to now. It's possible they did something illegal to gain access and if they did it's a high possibility the case will be dismissed due to the "fruit of the poisonous tree doctrine": http://www.law.cornell.edu/wex/fruit_of_the_poisonous_tree
Even if the government did something illegal, will the judge really let Ross walk free?
If he is allowed to walk free, that will set an example to all the illegal and drug lord out there not to fear the government.
He was simply 'lucky' this time I guess. They wouldn't go to unreasonable length to convict him. I bet the evidence was already quite a stretch and they knew it. They risked it and it didn't work, it wasn't recognized. That's the way it works.
Oh he hasn't won the battle yet! Just to note: he has only made an argument. He is still in jail and still being charged, nothing has changed yet, we have to wait to see what the FBI's repsonse to this will be.
In order to give them back to their previous owners 
