Difference between syntax class `escape' and `charquote'

["Tobias C. Rittweiler" <tcr@freebits.de>]

From isearching through src/syntax.c, it seems that the `escape' and
`charquote' syntax class are interpreted synonymously. 

The documentation says

     [A character quote character] differs from an escape character in
     that only the character immediately following is ever affected.

What is this supposed to mean? How can an escape character not affect
the immediately following character?

I'd also like to ask for this being clarified in the documentation.

Thanks!

  -T.