Every diver learns a pre-dive check. Most stop doing it properly within a year, and the reasons are exactly the reasons people skip code review.

The failures it catches

Air turned on but not fully. A weight belt threaded the wrong way so it cannot be dumped. An unfamiliar inflator hose. A dry suit zip nine-tenths closed. Every one of these is invisible to the person wearing the kit and obvious to anyone standing in front of them.

That asymmetry is the entire justification. It is not that your buddy is more competent. It is that they occupy a different position, and the errors in question are position-dependent.

Why it gets skipped

• It implies distrust. Checking an experienced diver feels like an insult, so people perform a gesture instead of a check.
• Nothing has gone wrong yet. The check has no visible output when it passes, which is the same reason tests feel like a tax until the week they don't.
• Time pressure. On a busy boat, thoroughness looks like holding everyone up.

What makes it stick

Doing it in the same order every time, out loud, and touching each thing rather than looking at it. Touching is the part people drop first and the part that catches the zip.

The parallel with review is not decoration. Both are cheap, both are unpopular, both catch a specific class of error that self-inspection cannot, and both get abandoned by exactly the people most confident they are past needing them.