Now that is quite interesting. As others have pointed out turning a phone off could provide evidence against you.
Leaving it at home, or having someone else carry it with them could provide an alibi.
It’s a truism, but location data for a phone only proves where the phone was. Or where the phone thought it was. I wonder how quick a prosecutor might be to point this out. Especially when they might be less quick to do so if the location data suggested your phone was at the scene of the crime.
I wonder if you could poke a hole in that (widen the "where it thought it was" doubt) by pointing out incidents like when Facebook thought nearly everyone was in Philadelphia for a few hours.
My phone infrequently thinks I've left home without actually moving - far enough to trigger the 400m geofence around it and to switch the webcam into "I've gone out, HIGH ALERT TIME!"
I assume it's because it's not getting good GPS (I'm inside a block of flats), there's no cellular signal, and therefore latches onto a visible WIFI SSID (I can see 15+) that it's got a location for which just happens to be [somewhere else].
(Similar to when my phone used to think Euston Station was in Manchester because it was picking up the SSIDs from the trains as part of AGPS.)
Damn I always get left out of everything :-( lol I posted "Man it's weird having my house in Philadelphia" or something along those lines when it was saying that and I saw a friend that I hadn't seen in a while the other day and he was like "Hey I thought you moved to Philly? What're you doing here?" haha
Presumably that isn't a great alibi though. The activity on those devices probably wouldn't match the "normal" activity when one is home, so I suspect it would be easy for a prosecutor to argue that the devices were just left at home.