I would choose one option for the behavior, and leave it at MAY. I also think we probably don't want to do this unless we can convince people that it's not a privacy risk at all.

After giving this some more thought, I think there is enough complexity here that we shouldn't delay this draft while we figure it out. For example, it might make sense to say that the record ID is a 16-bit value indicated by a SvcParamKey (record-id=12345), and that record-id and port must not appear together. That would (arguably) make this unambiguously privacy-positive: it reduces the exposed entropy without increasing the total entropy.

I'm not sure that formulation would fly, but we should take our time and get this right.

Proposing to defer this to a future draft. It may make sense to do this as part of Alt-Svc-bis