[comboy]

What if somebody has a bad DNS resolver and what he qualifies as a valid DNS request, researchers do not.

I get the general idea, but having "user-privacy oriented" and "we collect everything and make it available to many researchers" services under the same IP may lead to some issues.

[cesarb]

Even a bad DNS resolver will still send to port 53. The privacy policy probably applies to anything on ports 53, 80, and 443.

[walrus01]

and the DNS over TLS port, 853

[Arnt]

Oh, in that case you can apply those issues to all of Cloudflare. They serve many thousands of websites from each node. God only knows how many different privacy policies may apply depending on which bytes you send to TCP port 80.