I had a coffee one day at Timothy's under TD Centre, reviewing my notes before a meeting. This table -- the one with the cell-phone -- was empty for at least 30 minutes, maybe longer. No idea where the person was. But no-one took the phone, it was still there when I left.
This kind of surprised me (hence the picture).
But maybe everyone who works in the financial district already has a phone.
Many neighborhoods would not have this kind of trust. In fact, my new gym has a sign about ensuring you lock your locker because they have had theft problems.
On the other hand, no one picked up the phone and tried to call the owner. That occurred to me, but would have seemed intrusive. A cell-phone is a pretty personal object, and touching someone else's without permission is an invasion of personal space.
Some things are so pervasive and foundational, we don't really think much about them. But when you are thinking about customer experience, you need to watch for anything that is odd, different, or interesting. And then ponder.