I don't doubt that there have been some missions where they willing sacrificed a few rings. An attack on a ship, an assassination followed by complete destruction of the fortress by damane, that kind of thing. But I think the vast majority of the time, they've gone in afterward (even if it's years later) with the intent to recover the rings.


And the Seanchan plan is still to eventually take over the Westlands, including Tar Valon. So I think they still plan to recover the rings.