The Orthodox belief is that when you die, you have to pass through 20 or so "tollhouses". Each represents a particular sin. If you have unconfessed sin, you will be stopped at the tollhouse pertaining to that sin, and thrust by demons into hell. On the other hand, your guardian angel is there to uncover the good deeds you have done, and place them on the scale where the sin is weighed. If people are praying for you, that goes on the "good" side. So, these people are in BIG trouble.