My only concern about the Blackrock/Obenauf treatment, and probably something Docride could answer, is that these products have carnauba wax for leather protection/waterproofing, so I wonder if that would prevent the conditioning done by Hermes from penetrating the leather as well. I've been told by my SA not to treat the leather myself, just send to H for care, but I don't see why just conditioning the leather is discouraged. I can see why they don't want waterproofing or dyes applied as it could affect what happens when H treats the leather. I doubt they could reject a treated bag unless something drastic has been done to change the leather, probably just get a lecture about not using anything in the future.