I'm not a big fan of Fox in the first place, so I won't retract it. :p
Out of the dozen HD DVDs I have (with several combos), my 360 add-on has only hiccuped a few times on initiating playback of Hot Fuzz. After restarting playback, it was all gravy. So I haven't personally witnessed all this combo misery as others have (yes, I don't have all the combo titles obviously).
Back to the topic, if Samsung/LG are to blame as you suggest, Fox wasn't incorrect in pointing the finger today.
EDIT: I should've knocked on wood because my 360 add-on is now hung up on loading Heroes disc 2.
- first time for everything.