Also, I’m thinking that line is actually drawn right over some text inside the tag... kind of like how you'd strike through something when you're correcting yourself?
True enough. It’s not like someone is actually going to strike through a word because they made a typo; they do it because they’re being snarky. It reminds me of that guy over at Geekology who seems to include a crossed-out word in every single post just to take a dig at someone else. 🙂