API: "email_alias" Is it possible to register other than the same domain?

At this time, if you disable it until the email address is confirmed with
the same specifications as when registering from the UI,
I think that you can prevent misuse.

Example)
Suppose a customer wants to give a user two email addresses in different
domains before the company integrates.
↓
This specification allows administrators to bulk register using
the API without user effort.