To quote the source:
====================<p>Verify: the email address of the Registered Name Holder (and, if different, the Account Holder) by sending an email requiring an affirmative response through a tool-based authentication method such as providing a unique code that must be returned in a manner designated by the Registrar, or<p>the telephone number of the Registered Name Holder (and, if different, the Account Holder) by either (A) calling or sending an SMS to the Registered Name Holder's telephone number providing a unique code that must be returned in a manner designated by the Registrar, or (B) calling the Registered Name Holder's telephone number and requiring the Registered Name Holder to provide a unique code that was sent to the Registered Name Holder via web, email or postal mail.<p>In either case, if Registrar does not receive an affirmative response from the Registered Name Holder, Registrar shall either verify the applicable contact information manually or suspend the registration, until such time as Registrar has verified the applicable contact information. If Registrar does not receive an affirmative response from the Account Holder, Registrar shall verify the applicable contact information manually, but is not required to suspend any registration.
====================<p>So there are other methods that ICANN outlines in order to verify the account holder information to activate the domain, not _just_ an email address like the article states.