You don't. You take this risk with many other products and services as well. Sometimes you get burned, and that's life.

The best thing you can do is trust a company's reputation. And let's just say that Activision hasn't given me any reason to trust them for the past 10-15 years. Why people still do so, I have no idea. If you enjoy their games, then more power to you. If you find yourself complaining constantly about their releases, then perhaps you should reevaluate your spending choices.