The device id is the subscriber-only pseudonymous handle, used as the join idempotency key and to address this device in the delivery ledger. Use SecureRandom through the native bridge, validate it against the service limits, and keep hardware identifiers out of it entirely. Device labels describe the device role, never a slice of the id, and the subscriber list renders the wire id/created/lastSeenAt fields.
The blocking grants (exact alarms, full-screen intent, notifications) and the advisory battery exemption are surfaced as readiness, not as warnings that still allow arming. Listening state is read from the persisted native record on resume so a process-killed service cannot leave a stale armed claim on screen.