It doesn't mean the retailers would necessarily get stuck with the tab. They might even pick up a few bucks.

Small aluminum recyclers have shops all over the country; presumably they make a profit or they wouldn't stay in business. Soda bottles used to be made of glass and payed a 2 cent return deposit. Supermarkets regularly bought them back in quantity.

This oil belongs to BP, there is nothing inherently wrong in asking them to pay to have it returned to them.