Someone I knew once sent me an urgent direct message over Twitter that they were stranded in the City of London and needed me to wire money. Phone gone, computer stolen, they could only communicate by Twitter. Of course it wasn't actually my friend, but a 2-bit hacker. But if they were to collect enough accounts and message enough people, someone might bite. Maybe someone would give up something truly valuable if they really thought it was someone they cared about, a long lost son, or a pined-for ex.