I could not get this logic. Can you explain more? problem would have been, if he got that money before demonetization, or he would have bought lands/gold, even then , if money comes in bank, "blackness" goes away, no?
Just few days before demo, huge huge amounts of cash was deposited in his managed loxal bank, & when demo was declared, as that money was already in bank's vault, it was safe. Also, the bank was type of Co-operative, kind of local credit union, these types of banks does not need to be interconnected between branches or with a central place, neither do they need to keep digitally timestamped records, manual book keeping on paper is allowed.