Yahoo did respond late Wednesday night with a statement pointing out that all members agree to abide by the Flickr community guidelines, and concluding, "The Flickr model is based on an open community that thrives on sharing and discussions and that monitors itself for abuse. Our members have always done a great job of identifying inappropriate and offensive content on Flickr, and we encourage our members to continue to help make Flickr a respectful and safe community to share photos and videos."
None of which answered my questions, which were: When an account is deleted, why can't Flickr give the user some notice before deleting photos so the user can back up his/her photos if necessary, and/or appeal the decision? Wouldn't that be more reasonable and humane? Isn't it possible that an account could be deleted in error?
So I re-asked those questions, and am again awaiting a response.