Let the system go long enough and everything becomes accidentally load bearing. See also "implementation becomes the specification" - people will come to rely o

Let the system go long enough and everything becomes accidentally load bearing. See also "implementation becomes the specification" - people will come to rely on every single undocumented implementation detail regardless of what the official spec says. That's why it is a good practice to have DiRT or similar exercises. Break things on purpose so that people don't rely on them when they shouldn't.