Aside from being stolen, would there be any occasion when the 3G would not be on? I know with my iPhone the minute I no longer am in range of my wifi or a wifi that's stored on my phone, the 3G comes up. Also isn't there a 'last known location' thing with iCloud? To be honest I haven't looked into it too thoroughly myself, but I seem to remember seeing something about that.
As far as I could tell, It only shows the last location that a successful query was made....
Another thing I found....by accident...I have a set of Bluetooth headphones to listen to music when walking and it also made it easy in the winter to answer the phone....wouldn't have to dig in my pockets in the cold.. Walking out the door the other day, the music suddenly stops....turns out that I had left my phone on the kitchen table...
That got me to try and research for a Bluetooth tether for the phone that would give a warning if one gets too far away from the other....You get the implication...prevents you from loosing your phone...
They do exist...now the only thing I need if for someone reading this post, to suggest, a make or model to me...;-)