I don't think the SPCA (or any other animal welfare group) should be partnering with any stores (such as Petcetera), that sell purposefully bred animals.
But just for a start, the SPCA could choose to refuse any partnership with Petcetera unless every rabbit sold is already spayed or neutered.
The SPCA is deliberately choosing to be part of the problem of rabbit over population.
In my eyes, that makes them directly responsible for the large numbers of dumped rabbits.
Perhaps if they HAD to take responsibility for caring for all these unwanted rabbits for their entire lives, they might make the spay/neuter connection.
Shame on them, Petcetera, and the morons who dump their rabbits as if they are garbage.