AI traffic and how much data transferred in a VATSIM-se

I plan to join VATSIM and therefore seek for as many infos as I can get. Since this here my 2 questions:1. I have heared it is possible to leave AI traffic enabled during a VATSIM session. But how should this work? I assume the controller won't see my AI traffic. So e. g. he/she may clear me for landing, not seeing that I have actually got an AI plane on the same runway lined up for take off.2. As I am on a DSL connection with limited datatransfer volume (1 GB per month) I'm interested to know, how many KB or MB are transferred per hour during an average VATSIM session.Thanks in advance for your replies,Wolfgang