Sandisk one works this way exactly. When you check the same code second time, you get the message '您输入的防伪码正确，但是已被查询过，您可以拨打400-670-6711进行人工查询,我们可以提供首次查询时间以及查询方式' (translation - 'The security code you entered is correct, but it has been queried. You can call Sandisk customer care for manual query. We can provide the first query time and query method.') with 'attention!' sign.