Because...hardwood flooring is in fact unstable (believe it or not) when it comes to covering it with a rigid ceramic tile installation. It moves slightly in all directions with seasonal changes, atmospheric changes, yada yada, and such but as a hardwood floor the movement goes unnoticed. Place a hard rigid tile floor over it and you can be asking for serious trouble.
OK I stuck it in the memory bank. Thank you
Where else have you looked?
Why would I look somewhere else I already know everything just ask me ( but not the wife or kid).