For the "no response" case, e.g. clients ignoring the retry-after header (or in the particular situation where I learned this trick, retrying aggressively on 40

For the "no response" case, e.g. clients ignoring the retry-after header (or in the particular situation where I learned this trick, retrying aggressively on 401) one can implement an "err200" response in the load balancer which makes them all go away ;).