What this article doesn't explain are the ambiguous ways of crossing the line - if a cyclist leans forward and their nose crosses before the front of their tire

What this article doesn't explain are the ambiguous ways of crossing the line - if a cyclist leans forward and their nose crosses before the front of their tire, from where is it measured? How about their hat? If a runner's belly is larger than their torso (OK, unlikely) does that count? I have seen some articles discussing this during the last olympics, and remember thinking how much more impressive it made the job of measuring completion.