Would it be possible to somehow merge this to lists?
If I add someone to my contact list, then its 100% sure that I want to receive emails from that person.
In other words, that user will bypassing all security test on SMTP level, just as whitelist contacts.
This is useful since mailbox users dont have to manage 3 different type of listings.
"Contacts" will become more useful, other than just a phone book style.