There is a downside to letting half of the team off. If our most important players sit and the rest are mixed with back-ups, there is more concern about injuries.
You can't go in planning on a loss but starting half of the starters, that is a recipe for disaster. Either go all in(minus Romo for most if not all of the game) or sit the most that you can and tell them to just go through the motions.
In my experience in playing sports, if you play to avoid injuries, they happen more frequently. It is in the back of their minds to avoid contact, etc.
They have two options:
1. play to win
2. plan on the loss and use a simple game-plan while resting as many as they can
But, it is difficult to do both.