yeah I hated when one of the adventures had some weird things were you had to do things in order but my players broke the order by useing common sense... I rolled with it
Even if the DM had read the DMG2 (I don't know if he did or didn't), I think it was the Phantom Steeds that were a bridge too far. The adventure used a system of "fatigue points" that wanted to make your struggle to survive and get to your destination in a timely manner more exciting.
I remember the DM specifically running this trilogy of adventures because he'd played them at a Con (I want to say CODCON at the College of DuPage) and thought they were challenging, but our group kept making a mockery of the challenges.
For example, halfway into the adventure, you have to fend off some bandits or whatever that have a dragon in a cage. The cage has a tough lock, and you need to get it open during the fight.
One of the guys was playing a strange Eladrin Fighter build that I don't remember the name of, that allowed him to teleport around; one of the things he could do was Misty Step and bring people with him. So he reached into the cage, touched the dragon, and Misty Stepped.
The DM just blinked at him, read how the ability worked and we went on our way. So it may just be that we were frustrating him with a nonstandard approach?
(I could also bring up the Wizard's use of Force Ladder to try and foil the tremorsense of some Bulettes in a later encounter).
This goes more into the "Orcs on Stairs" discussion, obviously, no adventure writer can predict what players will do, and this was an adventure designed to be completed within 2 hours or so, so I wouldn't expect much guidance on troubleshooting.