Oh come on! An illegal operation has no legal ramification. It is purely a technical term within computing parlance. But nice try though. LOL.
I disagree. Software is very pernickety, and is governed by laws - regarding what can and can't be done in given contexts. 'Pernickety' is outrageously anthropomorphic, I know (you'd understand my paranoia if you knew how long I've wrestled with the stuff ), but the same anthropomorphism underlies the words 'governed' and 'laws'. 'Illegal' in this metaphorical usage seems to me extraordinarily appropriate.