warn-before-the-thing-you-are-warning-about

Something a user is about to do has a consequence they will not expect: an unsigned installer their OS will block, a command that rewrites history, a setting that removes a human from a loop, an export that leaves the sandbox.

It does not apply to consequences that are obvious from the label. "Delete" does not need a paragraph explaining that it deletes.

1. Put the caution above the control, in the reading order, not below it and not in a tooltip.
2. Say what will happen in the user's terms — the exact dialog text they will see, the exact error — and then what to do about it.
3. Reserve interruption for the irreversible. A confirmation on a narrowing action trains people to click through the confirmation that matters.
4. If the surprise is unavoidable and benign, explain why it happens. "There is no code-signing certificate" converts an alarming dialog into an expected one.

Front-loading cautions makes a page feel heavier and can scare off a user for whom the risk was never real. That cost is genuine and worth paying only where the surprise is genuine.

The failure mode of over-applying this is a product that reads as nervous about itself. If every screen opens with a disclaimer, the disclaimers become chrome and the reader skips them — which puts you back where you started, with worse copy.