Just found this on my iPhone! What a fantastic option. It automatically switches on from 5.30pm through to 9am. So basically it means calls get automatically diverted through to voice mail. Unless they are in my favorites list. Text messages and emails come through but silenced so that i can live with. Really nice option to have as work calls is insane. Today has seen 13 landline calls come in and 16 mobile calls. I think the record is something like 34 calls in a day!