It would be interesting to run CalDav and CardDav compliance tests against all the providers and see who's actually compliant. This seems like a "We don't want

It would be interesting to run CalDav and CardDav compliance tests against all the providers and see who's actually compliant. This seems like a "We don't want to deal with someone wondering why their ______ service won't work even though it's returning a completely invalid response" decision.