I wasn't taught scales so I worked out fingerings for myself. Later on I found that my fingerings mostly coincided with the "orthodox" ones aside from certain positions in the double-note scales, e.g. thirds, which I had concocted to better suit the size and shape of my hands.
However, as rc rightly says, how often does music involve just going up and down in the same pattern ? Even in pieces where scales do occur, for example the beginning of Mazeppa or in the Ab polonaise, they are usually altered in ways which necessitate rethinking fingering from scratch anyway.
Once in the area of improvisation, I find the use of ordinary scales and other conventional playing forms too uninteresting musically. The natural inclination is to break them up into spontaneous, irregular sequences, put extra notes in, leave some out and so on. Fortunately, there is no correlation between difficulty of fingering and quality of resulting sound, so an easy scale formation conceived on the fly is likely to sound more striking than something worked out.