Who would go on the NYC Subway wearing $1000? There is a time and place for that, but there is also a thing called 'keeping it on the down low'.
I believe that the guy was carrying about $1,000 in cash. He may have been on his way to buy something - licit or illicit - and got nailed because someone knew he was carrying that much cash.
One would be surprised at the amount of cash that gets carried around in NYC, even for licit transactions.