Notification settings doesn't actually affect event generation.
Ok; I suspect that this is because I just don't recall the Reports featuring 'Inactive' events before (I wouldn't have been looking for them).
I still have some questions about events, though, regarding their creation and interpretation.
Here's a screenshot of part of an 'Events' report, for the iPhone:

Outward journey:
09:43: I opened the Traccar Client app, and switched on Continuous Tracking. Left home (geofence).
09:44: Device moving event essentially at the same time as the Geofence exited event, I assume.
09:53: There is a Device Inactive event, however the iPhone was still moving at this time (I was driving), so why would an Inactive event occur?
10:08: I stopped moving at / around this time. There is a second Device Inactive event, at 10:08, but no Device stopped event was ever created (until perhaps later? See below).
10:16: I switched off Continuous Tracking, and closed theTraccar Client app, sometime before this event.
Return Journey:
14:57: I opened the Traccar Client app, and switched on Continous Tracking.
14:59: Is this actually the Device stopped event that I 'should' have received at the end of the outward journey? If so, why delayed?
15:01: Device moving event; probably when I started driving.
15:08: Again, a Device Inactive event, but I'm still moving.
15:22: I arrived home (Geofence entered).
15:23: Device inactive; perhaps when I switched off Continuous Tracking, and closed the Traccar Client app.
15:35: Status unknown (I guess that's when data stopped arriving).
15:38: Another Device inactive... But why no (new) Device stopped event created?
Key questions:
Why are Device Inactive events created while the phone is still moving?
Why are Device stopped events delayed (outward?), or not created at all (return)?
I recommend reading the documentation before asking more questions.
Sorry, I'll do that.
I thought I had read it, but I now realise that I need to read it more closely (particularly the section about Motion).
It's an iterative process, probably quite typical; Read, do something, read some more (if one remembers to), do something more, repeat.
After removing the Connection to the notification for the iPhone, and un-ticking the 'All Devices' checkbox, notifications are no longer sent.
However 'Inactive' still appears in Reports, for the iPhone.