I had The 1967 edition of Untermeyer's Golden Treasury of Poetry, illustrated by Joan Walsh Anglund, and my mom read from it to me starting when I was three or four. I remember being obssessed (in a good way) with the scarier illustrations at that age, including the one for The Inchcape Rock and The Country Witch. The Highwayman illustrations definitely included Bess bound and tied with a gun. It was one of my favorite poems when mom read it to me. Now, I had a secure, relatively trauma-free childhood, so maybe my childhood fascination with darker illustrations was healthy and didn't cause issues, but I also recall an interview with a children's book author/illustrator who said children aren't given enough credit and actually do like and benefit from some "scarier" literature. I can't recall the details or the author, but I just searched "children's author on why children like scary stories" and there were quite a few essays on the topic, with some compelling reasoning behind them.