Challenge 3: Diagnosing a Forgotten Mode Switch — Solution Walkthrough

What happened:

The colleague was still in Editing mode (the default) rather than
Suggesting mode when they made the change. Because Editing mode
applies changes directly to the live document with no distinct
"proposal" state, the paragraph rewrite appeared to every current
viewer exactly as an ordinary, permanent edit — no strikethrough on
the old text, no underline on the new text, and no accept/reject
icons anywhere, since nothing was ever held apart as a suggestion in
the first place. This is not a bug or a glitch; Editing mode
genuinely did exactly what it's designed to do — it just wasn't the
mode the colleague actually meant to be using.

The single check that would have prevented it:

Glancing at the mode switcher in the top-right corner of the
interface BEFORE making the edit, confirming it actually read
"Suggesting" rather than "Editing." This is a simple, one-glance habit
— but it's precisely the check this chapter's own warning box
recommends, since the two modes look identical in every other respect
except for that one indicator and the resulting visual treatment of
the edit itself.

WHY THIS WORKS AS AN ANSWER
------------------------------
This is a direct, realistic instance of this chapter's own warning box
scenario: recreating Chapter 2's "no private staging area" risk isn't
a flaw in Suggesting mode — it happens specifically when someone
intends to use Suggesting mode but never actually switches into it,
making the simple habit of checking the mode switcher first the
entire fix.