i thinks its about proper recycling, its nice if you dont have the environment to do it in the area in which you live. if you are able to, then its irrelevant.
I feel like the cost of loading up a truck and return shipping it would very quickly outweigh the benefit of recycling unless it was done in bulk. Besides, if it was about recycling, then damage would be irrelevant.
some of them have collection boxes standing around, which only get emptied once a week or even less regularly. but yes, there is probably some like you described too.
When I did shipping and receiving we did exactly that. We'd make bales of cardboard in our baleing machine and stack the bales in shipping container and sent it back. They paid the store like $20 bucks per bale.
Where I lived at the time all shipping containers came in and went out on the barge so filling them up vs having them empty was a negligible cost difference according to the shipping company.