It is quite common to use things like line drawing characters in illustrations. With the new line height on code blocks, this looks even worse than before.
Real-life examples
From here
┌───┬───┬───┐
│1 1│1 2│1 3│
├───┼───┼───┤
│2 1│2 2│2 3│
├───┼───┼───┤
│3 1│3 2│3 3│
└───┴───┴───┘
From here:
┌→────────────────────────────────────────┐
│ ┌→┐ ┌→┐ ┌→┐ ┌→┐ ┌→┐ ┌→┐ ┌→┐ ┌→┐ ┌→┐ ┌→┐ │
│ │0│ │1│ │2│ │3│ │4│ │5│ │6│ │7│ │8│ │9│ │
│ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘ │
└∊────────────────────────────────────────┘
From here:
┌─┴─┐
×/ ┌─┼───┐
⊢ ÷ ┌─┼──┐
+/ - +⍨
From here:
┌──────┴──────┐
┌──┼────┐ ┌──┼──┐
┌┴┐┌┴┐┌──┴──┐ ┌┴┐┌┴┐┌┴┐
│⊢││~││∘.× ⍨│ │≢││↓││⍳│
└─┘└─┘└─────┘ └─┘└─┘└─┘