Helldritch
Hero
I differ with you as well. I claim the right to lie to the players. I claim the rights to modify a story to suit players' expectations or to contradict those same expectations if it brings up interesting plot twists. A DM not only has the rights to lie but he has the obligation to lie to his players when it is necessary.We can agree to disagree. Seems like a lie to me, but you might see it differently.
What he does not have the rights to is to cheat the dice in favor or disfavor of the players. He can't up the treath level of an encounter because they were smarter than he thought they would be or because luck was on their side.
An honnest DM is always true to the outcome of what the players do or do not do. But he can lie to the players about the means of achieving their goals. A DM is not there to restrict. In fact, I feel great as a DM when the players think of a way to solve a problem that I missed out. That door was ajar and they want to climb? Good for them, but if they get too soon in a difficult place, it will be on them. And if they get straight to the BBEG, so be it.