[dns-operations] When TLDs have apex A records

[Florian Weimer]

* Calvin Browne:

> As someone who helps to look after a (relatively) popular 2nd level with
> an A record at its apex, I can stongly warn against it. This is of
> course a different scenario from the tld example above but some of the
> lessons may apply.

A records at the second level are basically required if you care about
eyeball count because some folks inject ads if there's no A record,
inhibiting browser-based redirection, and some browsers do not
redirect at all.  (It may be called NXDOMAIN rewriting, but some
implementations are actually doing ANCOUNT=0 rewriting.)