Drush policy file to prevent catastrophes on live environments.

policy.drush.inc

<?php

/**
 * Implement of drush_hook_COMMAND_validate().
 *
 * Prevent catastrophic sql-sync to live. Note that this file has to be local to the
 * machine that intitiates sql-sync command.
 */
function drush_policy_sql_sync_validate($source = NULL, $destination = NULL) {
  if (strstr($destination, '.live')) {
    return drush_set_error(dt('You may never overwrite the production database.'));
  }
}

/**
 * Implement of drush_hook_COMMAND_validate().
 *
 * Prevent catastrophic rsync to live. Note that this file has to be local to the machine
 * that intitiates sql-sync command.
 */
function drush_policy_core_rsync_validate($source = NULL, $destination = NULL) {
  if (strstr($destination, '.live')) {
    return drush_set_error(dt('You may never overwrite the production files.'));
  }
}