Sometimes I use an editor with a highlight and comment feature, and if I comment out a block of code, some of those intertwined comments will have the double semicolon. Another neurosis I have is using multiple for stuff that I've yet to delete but want to make sure I don't accidentally uncomment but that is dumb and what version control solves. Outside of these unconvincing uses I'm not familiar with this nested comment idea but I couldn't criticize it given the funny things I do.