Is it possible to not have a default country?
CiviCRM allows you to over-ride the settings through php. You can over-ride default value for Contact Country. 

Add the below snippet in your sites civicrm.settings.php file

global $civicrm_setting;
$civicrm_setting['Localization Preferences']['defaultContactCountry'] = '';


Ref: Override CiviCRM Settings 

HTH

Pradeep