If you play it, enjoy it, and ESPECIALLY if you have it long enough to complete it, you ought to pay for it. That said, Square itself isn't necessarily obliged to get money out of you, but if not them than whoever is selling the game used.
This one incident won't bring down the industry or anything, but it would if it were possible to do on a wide scale. So in the grand scheme of things this is a non-issue, but it's certainly unethical all the same.