[anti-abuse-wg] Two simple questions about WHOIS data

1)  Within all of the domain WHOIS records that I have ever seen, there
    are at least the following data fields:

    Registrant name:
    Registrant Address:
    Registrant Phone#:
    Registrant Fax#:

    Which (if any) of these data fields is considered "optional" and
    which (if any) are "required"?

2)  In theory, at least, what is SUPPOSED to happen if, say, somebody
    reports to ICANN that a domain name WHOIS records contains false
    or fradulent information, and if, after that report has been sent
    on the relevant registrar, and thence, presumably, also on the
    the relevant domain registrant, and after a proper amount of time
    for them to be allowed to act has passed, and if by then the domain
    registrant has either refused to correct the WHOIS data or has put
    in new and different data that the original reporter claims is also
    false/fradulent, then, after this sequence of events, what exactly
    is SUPPOSED to happen?  Is the registrar then expected and/or required
    to suspend the domain registration?  Anything else?  Is the registrar
    also supposed to disable or hobble the registrant's own preferred
    DNS service/servers for that domain?  Anything else?