The late Stu wrote:

Sunlight, heat. Spine inward will prevent it, as will ensuring bookcases get no natural light.

That is great advice. I will follow this with the "standard" Folio set if I ever decide to get it. Right now I am only doing this with the author illustrated editions due to my fear of the nice silver and gold details being damaged.

Got another reply from a fantastic FS customer service representative:

Folio Society customer service wrote:

Hello [EmilK],

Thank you for your reply!

While we have no immediate plans to update the non-limited Folio Book edition of Lord of the Rings with the HC corrections or to release any new additional limited or non-limited editions of Tolkien's works, if you are signed up to our mailing list, you will get all the updates as and when they are available.

Kind regards,

At least the idea is gotten a +1 in their heaeds.