At least in the case of UPS "stores", they have zero connection to the actual UPS corporation. They simply rent the UPS name.
UPS stores are the remnants of the Mail Boxes Etc. stores in North America after it went bankrupt. MBE still exists elsewhere under different ownership.
UPS became the franchisor and rebranded the stores with their own name.
But they might as well be rebranded again, to "Amazon Returns Collection Store" based on the traffic I've seen. 80% of their business my closest branch seems to be acting as Amazon's customer service counter. Post-holidays, the space resembles a hoarder's dream, piled with Amazon returns.
Conversely, after Kinko's was acquired by FedEx, their name was expunged only after the second rebranding, to simply FedEx Office, which are all corporate-owned.
On the whole, I've had better experiences at the UPS stores.
Amazon told its sellers last fall it was ending the commingling program, at the end of March. Before, sellers could avoid it by paying extra fees to reserve their own space.
Now, it needs to address its returns processing to do more than just slap an LPN sticker on the box, or throw it in a plastic bag, before resending the item to the next buyer as new.