You were reading Murakami and smiling at the pages, oblivious to the world. I was the guy in the Mets cap who kept trying not to stare—do you want to finish our subway conversation over coffee?
Never pay down a deposit in a bank account until you have met the seller, seen signed a purchase agreement.
No serious private advertisers ask for a down payment before you meet.
Receiving an email with an in-scanned ID does not mean that you have identified the sender. You do this on the spot, when you sign a purchase agreement.