From PGC Facebook:
UPDATE - Regarding challenge checkers and privacy settings
Earlier this evening we were instructed by Geocaching HQ that we should revert the change made Tuesday morning (CET) to Project-GC Challenge Checkers. As such, we have once again made Challenge Checkers possible to execute irrespective of the ‘Geocaches found’ privacy setting.
Thank you to everyone for your patience while we navigated the complex situation in cooperation with Geocaching HQ. This past week has involved challenging discussions, both with the Lackeys in Seattle as well as members of our community. We are now happy to be back on the same page as Geocaching HQ.