I honestly never copy-paste from StackOverflow. I go there for general pointers or look at the code snippets and will only use what I think I figured out, and then write code myself.

Even that cannot really protect me from missing things like the security implications that this blog post talks about.

In this case, I probably wouldn't have fallen for the stuff CoPilot (or an equivalent SO answer) suggested, as I learned about these kind of injection issues a long time ago, but there are certainly a lot of areas where I would fail miserably to detect subtle (security) bugs. APIs are full of subtle and often non-obvious pitfalls, and even algorithms can be, where the algorithm seemingly works except for non-obvious edge cases that you might not have considered.