Yes, tuning a piano must be a subtle art, because I have heard that the great classical pianists (Artur Rubenstein, Vladimir Horowitz, for example) would not only haul their own pianos around with them when they went on tour, but bring their favorite tuner with them, too. (I mean a person, not an electronic device.)

I remember hearing one such tuner being interviewed on NPR, commenting on how temperamental pianists could be. One pianist flew into a panic because someone had cleaned the keys of his piano. He had always insisted that the keys never be cleaned because it changed the "feel" and made them too slippery. He thought his piano was ruined. The tuner saved the day by spraying the keys with hair spray.

Maybe that's the kind of helpful hint that gets printed in "Piano Tuners Quarterly."