If you have the prospect of having to face both Australia, and then New Zealand, would you
a) Send in your best players to face Samoa
b) Rest your 'top players' so they are ready for the 2 upcoming matches (and not out to injury)
You follow option B. There is a
a) Loss, and we face Ireland (the Australia beaters), England, and then New Zealand in the final
b) Win, and we face Australia, New Zealand, and England in the final
So the odds are on that we could face Australia (or the team that beat them), New Zealand either way, Ireland who just prove they can beat Australia, and/or one other team.
I think the decision is way more technical and tactical than purely 'throwing a game'. And the players wont have much of a say. It will be setup for one or the other route.
What could suck is putting in a full strength side to beat Aus, then beat New Zealand and then rock up at the final with injuries/tired players, and suffer a gifting defeat to England or heaven forbid, France. Or Ireland! The goal is to win the world cup - not beat every top team. No one cares about a "free win" or other mocking comments. It's the silverware and the title...thats all. Coaches will strategise accordingly.