The core charge is refunded to the purchaser when they return the core (old battery). Not sure how this is a factor.
I have dealt with some (12V automotive) battery companies where they supposedly had very strict environmental regs to follow. They had to receive and recycle 1 used core battery for every new 1 sold (or else the feds could fine them). It wouldn't be inconceivable that Toyota set up similar regs- esp considering just how many hybrid cars and batteries they have sold. Posted via the PriusChat mobile app.