Answer
Only the chosen list is connected to another device by QR code or pairing code. List-specific keys are exchanged in the process. Changes are transferred as encrypted list events via a relay service; the service is not meant to receive the actual list contents in plain text. Other local lists are not automatically shared by this.
End-to-end encryption does not protect against every problem, though. Anyone with access to an unlocked paired device can see the list there. A pairing code shared by mistake also needs to be taken seriously. A local change only reaches other devices once the transfer has worked. If something goes wrong, the platform, app version and affected list are important details for support.
As of 3 September 2026
Further reading
Related topic: PickQueue