Want to keep your privacy policy?
Most alliances suffering the war rating reduction are mostly innocent. They are suffering because of the actions of a few, sometimes one person. It would be nice for Kabam to rethink their privacy policy and release the names of players that violate ToS to at least the alliance leaders but here's a very easy way to maintain your policy but help the player base immensely.
Simply remove the player from the alliance. That way they can easily be identified and blacklisted but you did not technically release any details so you still maintain the privacy policy. The alliance will still get the war rating reduction but at least they don't have to go on a wild goose chase trying to figure out who caused the drop