Yeah true but the problem with chargeback happens regardless of whether somebody bought the codes or not - unless they bought the codes with stolen credit card,

Yeah true but the problem with chargeback happens regardless of whether somebody bought the codes or not - unless they bought the codes with stolen credit card, and then the store selling it, not the developer, gets the chargeback. So I don't think this scenario applies here. Developers usually have publishers to deal with things like credit card charges.