Well the same would apply to ALL Churches claiming to be of God, not just the "Armstrong" Churches. But it still applies to them.
I have caught people from that set of believes blatantly twisting scripture or falsely prophecying also, but that was the individuals decision to do so, not a doctrine set by Armstrong. Though, Armstrong himself had "prophecied" about events that just did not happen. That in it's self should be a red flag, yet his grip on the followers is so strong that even though when his many prophecies did not come to pass they still bow to him. They then make up excuses for him for his falsehoods. Taking his words(his interpretation) as the word of God.
The history of that Church is interesting to say the least... I'm not in that church, yet even I was effected by those teaching, for good or for bad.