I think we're being a tad flippant with the banter about who "packed" the boxes. There are only a select few people who have the clearance to even view TS/SCI level material. So if anyone who did NOT have that level of security clearance even touched, mess less "packed" those boxes that is an extremely damaging revelation. That is precisely the level of nonchalance that the NARA complained about regarding Trump's unwillingness to adhere to security protocol that they earlier observed when he was still in the WH...
Saying that Trump didn't "pack" the boxes is not exonerating, but rather damning. That TS/SCI designation is reserved for documents only allowed to be seen by a highly selective group of people in a secured (as in armed guard posted outside the door) type of location. People are required to pass thru metal detectors and surrender all electronic media devices prior to entering that location.
And the idea that Trump might have "declassified" them prior to leaving for MAL doesn't hold water either. With a TS/SCI designation, Trump can't just "declassify" them for his personal knowledge. He has to inform every other person who has clearance to handle them (like the House Intel Committee), because once they're declassified they are no longer restricted to people with that clearance.
That means they are no longer protected by armed guards and all of those security measures. But that level of declassification can't just be done "willy nilly" and often requires months to complete. And until everyone involved was notified and the security concerns were addressed, any claim by Trump that he declassified them is completely meritless.
The fact that whoever turned informer saw those type of markings, realized the implications and contacted the FBI to report it, removes any possible validity for Trump to claim he didn't know they were there. At the very least he exhibited gross negligence...