> There is simply no excuse for turning on Find Friends, setting a reminder to tell you when somebody else leaves a location, having it not remind you and then having to troubleshoot to figure out why.
Yeah there is an excuse: you deliberately and explicitly told it not to remind you. Either by deliberately and explicitly turning off Background Refresh. Or by deliberately and explicitly killing the app. In either case, the user took an action to opt out of receiving these reminders.
Could it be clearer? Possibly. For example one could put big giant "you don't want to do this" confirm dialogs whenever the user disables Background Refresh or kills an app. But those are annoying, and everybody just presses "yes" anyway, so I'm not sure the situation would be materially improved.
> When I have Reminders open in the background, the location icon is active but outlined in the taskbar. When I have reminders closed but Find Friends open in the background instead, the location icon is colored white in the taskbar and appears momentarily before disappearing approximately ten seconds later (even if the app is still running in the background). I have absolutely no idea what that is
The short answer is that there are various different technologies involved in determining your location. This information matters to developers and some power users playing games with iOS system settings and so they have slightly different apearances in the status bar (filled in vs not filled in for example). From a user perspective the important thing is that a triangle in the status bar (whether filled in or not) means some app is using your location data. Different apps in different circumstances need different kinds of location data and so the change in what is drawn there has to do with what kind of location data Reminders or Find Friends has requested from the system.