Backbone save issue

gistfile1.php

///////////////////////////////////////////////////////////////////////////////////
// Generate People
$sync = new BLAH_Sync_Person(array('client'=>$ldap_client));
foreach(file('people.csv') as $line) {
    list($name, $gender) = explode("\t",trim($line));
    $attrs = array();
    
    //Personal
    $_names = explode(' ', $name);
    $attrs['title'] = ($gender==BLAH_Person::GENDER_MALE) ? 'Mr' : 'Ms';
    $attrs['surname'] = array_pop($_names);
    $attrs['given_name'] = array_shift($_names);
    if ($_names) $attrs['middle_name'] = trim(implode(' ', $_names),'.');
    $attrs['gender'] = (int)$gender;
    
    //Contact
    $attrs['phone'] = array( sprintf('0499 %03d %03d', rand(0,999), rand(0,999)) );
    $attrs['phone_primary'] = $attrs['phone'][0]; 
    $attrs['email'] = array( str_replace(array('.',' '),array('','.'),$name).'@personal.example.com' );
    $attrs['email_primary'] = $attrs['email'][0];
    
    //Common
    //TODO: Make a note/log about generating the data. Maybe belongs in a 'log' array.
    //$attrs['notes'] = array( (stdClass)array('author'=>,     ) )
    
    $person = new BLAH_Person($attrs);
    //Show some debug output
    echo $person->toJSON()."\n";
    echo "------------------------------------\n";
    print_r($person->validate($person->attributes(), array('missing'=>true)));
    echo "------------------------------------\n";
    //Try to save the file
    $res = $person->save(null, array(
    	'sync'=>$sync,
        'error'=>function() { echo "ERROR: ".json_encode(func_get_args())."\n"; },
		'success'=>function() { echo "SUCCESS: ".json_encode(func_get_args())."\n"; }
    ));
    
    exit; //Debugging, exit after the first person
}

Model snippet - validate.php

    /**
     * Validate the given attributes according to the '$validation' rules and '$access_control' policies.
     * Return any errors in a map by attribute. 
     * If no errors are found, the response will be empty.
     * 
     * By default, missing attributes are not considered to be an error. 
     * 
     * Options:
     *  - missing : If set, return errors for missing attributes that have a rule 'required'=>true 
     *  
     * @param array $attrs
     * @param array $options
     * @return array empty if no errors exist, error message(s) if errors exist
     */
    public function validate(array $attrs, array $options=array()) {
        $errors = array();
        
        //Which values have changed?
        $changes = $this->changedAttributes($attrs);
        if (!$changes) $changes = array();
        $changes_allowed = $this->canWrite($changes, $options); //And which are allowed to be changed
        
        //Do all fields need to be validated, or just the changes?
        $to_validate = ($this->_previously_validated) ? $changes : $attrs;

        //Check all fields against the rules
        foreach($to_validate as $attr=>$val) {
            //If no rule exists, the attribute is invalid
            if (!isset(static::$validation[$attr])) { $errors[$attr] = "Unknown attribute"; continue; }

            //If that attribute has changed - check protections/permissions
            if (array_key_exists($attr, $changes)) {
                //Protections
                $error = $this->_validate_protection($val, $attr, $attrs);
                if ($error) { $errors[$attr] = $error; continue; }
                
                //Permissions - check that the user can write to that attribute
                if (!$changes_allowed[$attr]) { $errors[$attr] = 'Forbidden'; continue; }
            }

            //Check whether the attribute itself is valid
            if ($val !== null) {
                $error = $this->_validate_attribute($val, $attr, $attrs);
                if ($error) { $errors[$attr] = $error; continue; }
            }
        }
        
        //If missing attributes should be reported, check.
        if (!empty($options['missing'])) {
            //Which attributes are missing?
            $missing = array();
            foreach(static::$validation as $attr=>$rule)
                $missing[$attr] = (!isset($attrs[$attr]) or (!empty($rule['multi']) and $attrs[$attr]===array()));
                
            //Which missing attributes are required?
            foreach(static::$validation as $attr=>$rule) if ($missing[$attr]) {
                if (!empty($rule['required'])) 
                    $errors[$attr] = "Required";
                elseif(!empty($rule['requiredif']) and !$missing[ $rule['requiredif'] ] ) 
                    $errors[$attr] = "Required if '{$rule['requiredif']}' set";
            }
        }
        
        //Remember if the model is valid
        if (!$errors) $this->_previously_validated = true;

        return $errors;
    }

Output

{"title":"Mr","surname":"Willis","given_name":"Bruce","gender":1,"phone":["0499 535 964"],"phone_primary":"0499 535 964","email":["[email protected]"],"email_primary":"[email protected]"}
------------------------------------
Array
(
)
------------------------------------
ERROR: [{},{"id":"Cannot modify - readonly"},{"sync":{},"error":{},"success":{}}]