Setting context properties with \with

https://lilypond.org/doc/v2.24/Documentation/learning/modifying-context-properties

Under the heading "Setting context properties with \with", there are 
these statements:

     Properties set in this way may still be changed
     dynamically using \set and returned to the default
     value set in the \with block with \unset.

     So if the fontSize property is set in a \with
     clause it sets the default value of the font size.
     If it is later changed with \set, this new default
     value may be restored with the \unset fontSize command.

This is not the behavior that I see.  I see that \unset clears the value 
of a property that was established by \with just as if it had been 
established with \set.  For example, this does _not_ print a gigantic note.

```
\new Voice \with { fontSize = 20 } {
   \unset fontSize
   c''
}
```

Is this a documentation problem, or is LilyPond broken and I'm the first 
person to notice?
-- 
Dan