One of the small local shops nearby always has fire-bellied newts in with african clawed frogs. Another keeps a fire-bellied toad in with some kind of asian crab. Neither seem like a terrific idea to me.

On the other hand, I've never seen frogs mixed in the petsmarts I've been to. I've never seen more than 2 frogs at any given petsmart though, so it might just be the individual store or the timing of my visit.

Rescuing poorly kept animals seems like a good idea, but they'll probably just fill up the space again with new ones and are rewarded with a sale.