I used to have a wireless Logitech mouse that drained batteries if you didn't turn it off manually every time you finished using it. So I'm wondering about the Magic Mouse... 1. Does the Magic Mouse automatically shut off when the iMac goes to sleep or is turned off? 2. If I leave the Magic Mouse on (while the computer is off) will it drain the batteries? 3. What do you recommend is best for the batteries and mouse? Should I turn it off every time I go out for the day? Thanks.