, apparently +Motorola Mobility
has some plans for those who are selling codes; they've updated the sale FAQ:
Can I buy multiple Moto X phones with this promotion?
Technically, yes. But, each email address can be registered only once and a promotion code will only be valid on one device. If, by chance, you do have more than one code you’ll need to create separate orders and apply one to each phone
You’re not a store. We do not authorize using the codes for commercial purposes. If we detect you are applying for multiple codes for resale, we will not provide a code and we will invalidate previously provided codes.