[DNSOP] unsolicited HTTPSSVC responses

[Eric Orth <[e-mail]>]

One of my colleagues recently brought up the idea of suggesting recursives
add additional HTTPSSVC records into responses for A/AAAA queries as a way
to make HTTPSSVC more available for cases where a stub is hesitant to make
additional queries out of concern for bad behavior from bad middleboxes (a
frequent concern for Chrome when not using DoH).  My initial impression is
that it's not a reasonable idea, but I wanted to bring it here to DNSOP in
case anybody has further ideas to make it workable.  So any relevant
thoughts or concerns from anybody here?

The obvious problems I could think of (all basically along the theme of it
not being ideal when the stub might not even care about HTTPSSVC):

   - Performance implications if the recursive has to retrieve HTTPSSVC or
   follow alias chains.  Maybe not as bad if only done opportunistically when
   the recursive happens to already have everything in cache.
   - Polluting DNS for non-browsers.  Maybe not as bad if SVCB instead of
   HTTPSSVC, but this would likely only be of use for web browsers which are
   obviously not the only queryers of A/AAAA.
   - Could lead to lots of unnecessary truncation, especially for large
   records containing ESNI data.