I'm surprised that large amounts of dead code is neither an obvious-to-machines nor an obvious-to-humans problem or demerit with submitted assignments -- regardless of plagiarism status. I'd especially have thought such a clunky approach should be caught be a decent plagiarism detection software. It makes me wonder if simply feeding a student's assignment into Claude would be more reliable these days by just asking it, "If you remove all the dead code, is the remaining code likely plagiarized?"