Presence is not identity
One phone leaving does not mean the home is empty when other people remain.
Permissions can change
Operating-system updates or battery-saving settings can affect location events.
Use privacy-minimizing logic
Only collect or share the location data needed for the feature.
Avoid high-consequence actions without safeguards
Automations involving access or safety should have conservative confirmation and fallback behaviour.
Keep in mind. Compatibility is not permanent. Confirm the current manufacturer, platform and certification information before purchasing, resetting or migrating a device.