Runway 360:So nobody stops you from failing the game.
Actually failing requires a good reason. "I couldn't beat the game, so I can't test it." isn't a good enough reason, imo.
Passing on the other hand is completely voluntary. If you do not feel that you gave the game a thorough review, you are certainly allowed to just move on. If you feel the game has been tested well enough and you didn't find any fail points, then you are welcome to pass it. It would be nice if everyone tested every single feature, like MUs, but it isn't required, nor is it always possible.