Perhaps that's it. Seems a bit weird if you ask me - you have the infrastructure in place to record the game (I believe you can get full game highlights on certain packages, right?) but only if the game is broadcast somewhere live will the TMO be in place?
All very confusing!
If its anything like football, there are around 7 cameras in fixed positions, for a highlights game.
For a full TV game there are around 23, which would obviously give a TMO a lot more angles.
With a highlights package there will be several angles not covered.