This was a common approach at my Uni. I only once challenged it, but the issue was an entire question wasn't marked at all, so the lecturer didn't remark the re

This was a common approach at my Uni. I only once challenged it, but the issue was an entire question wasn't marked at all, so the lecturer didn't remark the rest. One other time, I asked the lecturer (different paper) where I went wrong on a question, and turn's out I was right all along, got that question regraded without the potential downside to a full remark.