According to a concert pianist who was on the radio the other day, Sergei Rachmaninov (he who unwittingly furnished the musical cues for the tear-jerk scenes in 'Brief Encounter') may have had a medical condition which caused his hands to grow almost an octave larger than most other people of his stature, making it next to impossible for the average pianist to play some of his more stretching works. I don't know why, but I find this quite funny - it's a sort of intellectual property defence, made possible by a freak of nature.
Luckily, Rachmaninov left behind all his concert compositions on audio recordings, so we know what they are supposed to sound like. When I was a kid, we had the ENTIRE boxed set of 78 RPM, brittle old records by him, and I listened to them a lot. I wish I still had them, they must be worth a few quid now.