Pretty sure a wire can be traced.
Of course it can... but Apple's cash is Apple's cash, and will be tracked throughout its journey from bank to bank and accounted for in every step of its transfer with GAAP accounting rules, or officers of Apple will be going to prison for a long time, not to mention $20 million personal fines. The Sarbanes Oxley Act of 2002 and the SEC will see to that.
There is no reason for Apple to sneak currency around on planes. Apple ships iPhones on planes by the pallet load. . . but those pallets are not that size. I've seen them.
What ever that is in the Q photo appears to either be in a land and sea box or a semi-truck trailer.
Why announce the buyback and then pay with untraceable cash?
The appropriate question is, “What’s in the box”
“Is whatever that is in the box moving from Cupertino, CA to Hong Kong in the bellies of regular commercial passenger flights?”