[0]: https://play.google.com/store/apps/details?id=com.google.and...
First time I'd read the description it looked like the recipient of the request had the option to grant / deny - which kind of defeated the purpose. Re-reading it looks like there must be some kind of time-out feature, where it will default to a response? Anyway - will give it a go.
There's a 5-minute delay, with a screen-on alert for the duration at the b-end, before you can get a geo-location response back.
If the 5-minute delay was configurable (I want it immediately), and the pop-up was a notification (sys-tray rather than full screen / break -screen saver) then it'd be a contender.
As it is, it's less useful than sending an SMS.
Thinking commute -- train then long walk home -- if convenient I'd rather share a lift than walk. Not the best example as I really should walk, but nonetheless.
With the gym scenario -- I know the days of week, and rough time, she'll be there, so not the best. In that case it's not the full screen pop-up that's the problem, just the hard-coded 5 minute delay.
Better example: early evenings, I'd like to know if she's working late or driving home. Without requiring that I interrupt her. If I SMS and she's driving, she has to break the law to respond. If I call (or SMS) and she's still working, that's disruptive. If I use Trusted Contacts and she's still working, also disruptive.
I'd never really thought about this stuff before the Google Maps article, and some of the discussion here -- it feels like my use case isn't that uncommon a thing. I may look at some of those family / kid-tracker applications, though last time I reviewed the field there they felt a bit clunky and overly intrusive.