Security section and increased load on authoritative name servers

[bjovereinder]

Security Considerations section mentions as threat extra load on authoritative name servers, possibly caused on purpose by malicious parties. This may be even more important for recursive resolvers.

[paulehoffman]

Recursive resolvers can choose to turn off TLS at any time, so this is not nearly as much of an issue for them as it is for authoritative servers that are committed to TLS service.