I suspect that their
styles betray a certain centrality of popular music to their musical imagination. In terms of 'serious' composition, this is the sort of music that notation programs tend to lend themselves to best, but I doubt their style is a symptom of their use (if they do at all) of notation software.
(did I mention litre bottles of correction fluid? - no, of course I didn't!)
We mustn't use correction fluid, as it might confound some occasional musicologists
. I prefer to use pencils anyhow. They are eraseable in the case of stupid errors, and a 2B pencil will photocopy to look almost identical to a pen.