Why wouldn't Customer A just get the (undoubtedly cheaper) stand-alone movie? And wouldn't Customer B just give up on getting the game if it was not only more expensive then he was planning, but bundled with a movie he might not have wanted? And why would anyone support a format that was only out to stiff the consumer base by depriving them of cheaper prices?
Pricing hasn't been announced yet, so all this is speculation, but if Sony plays its cards right, things could work out well.
For example, let's say the Transformers movie is $25, stand-alone game is $60 and combo is $70. Someone who wants the game could easily be upsold to the combo. Once they're done with the game they could sell it back to GameStop for $30, but then they wouldn't have access to the movie any more. And sure, you could sell the combo back and buy the movie and wind up with an extra $5 but the little extra dough probably isn't worth it to the customer. They'd rather keep the game/movie combo because having the game in their collection (for replay or to loan to friends) is worth more to the customer than $5.
Meanwhile, even though Sony gives up $15 worth of movie revenue, they more than make up for it via extra sales due to a reduced second-hand market. Obviously, this strategy won't work for every game. It'll work for Sony the most when it's a first-party game and a Sony movie. I don't have access to all the numbers, but it would likely work (albeit with a few tweaks) with third-party games and non-Sony movies.