All - thought I would start a new thread specifically regarding the early 2013 MacBooks. According to the Compatibility list, the Auto Unlock feature should work on these models, but I'm seeing other posts from users unable to see the option.
(The Auto Unlock feature is supported on 2013 and newer Macs)
I'm having the same issue - I know I have everything set up correctly since I'm able to see the option and get it to work on my 2014 MacBook Air - so I'm thinking there may be an issue with the early 2013's.
Anyone out there with an early 2013 MacBook able to get to work?