I'm not arguing with that, but lots of us can and do run our own DNS for various reasons, it should respect that, or provide a power-user way to override the de

I'm not arguing with that, but lots of us can and do run our own DNS for various reasons, it should respect that, or provide a power-user way to override the default DNS. By all means offer fall-backs to Google DNS if it's not behaving correctly, for the reason you mention. I've found it's also, quite poorly implemented, particular on CC Audios, I had an instance last year where my internet connection went down at my ISP, my DNS saw 10s of thousands of DNS queries per-device from each of my Chromecast Audio devices in the time I was out at work. It was almost 40k DNS queries in ~12 hours, per device. Almost everything else on my network behaved normally, but the Google devices just went mental spamming the network with insane numbers of impossible requests, back-offs are a thing, they should use them.