Yeah, it's of course very easy to cheat like that. The disturbing thing is that what you can do with studio editing nowadays probably constitutes a greater level of cheating (it goes well beyond splicing, believe me! - in fairness such things tend to be emergency edits where something wrong has been missed during the take and retake process.) I seriously considered videoing the track recording as a form of alibi!
In truth, as virtuoso left hand only pieces go, this is significantly easier than some Godowsky, for example.
For further info, my own track mini-samples can be found here:
https://www.pianostreet.com/smf/index.php?topic=63807.0Track listing:
1 Bellini-Jaell Reminiscences de Norma *
2 Bellini-Wright Col sorriso d’innocenza *
3 Donizetti-Leschetizky Andante finale de Lucia di Lammermoor
4 Rossini-Thalberg Moses Fantasy
5 Wagner-Liszt Lohengrin’s Admonition
6 Verdi-Wright Fantasy on Miserere *
7 Meyerbeer-Kullak Cavatine de Robert le Diable *
8 Massenet-Saint-Saens La mort de Thaïs *
9 Wagner-Liszt Fantasy on Themes from Rienzi
* denotes commercial premiere recording.
Approx 67 mins running time.