The MemberCsvBulkLoader responsible for exporting Members in the Security tab has this field

public $duplicateChecks = array('Email' => 'Email);

Shouldn't this field be changed to a static field so that it can be set in the _config.php file as well?

Currently we can use
Member::set_unique_identifier_field('MyNonEmailIdentifier');
to set the desired ID field for our Member dataobject, would be nice if MemberCsvBulkLoader maps its duplicateChecks field to the static $unique_identifier_field in Member.