I still think you'd be fine. The blue would only rub off if you're constantly taking them on and off the shelf. Otherwise they are just sitting next to each other. Also, even if some blue did transfer over to the white it should rub right off again. Personally I'll be keeping my copies of the Doubleday Years together.
My post about the material was also more for anyone who was worried about any "risks" involved in using white material.