It is ok for a mode to use @code{font-lock-face} for some text and
also use the normal Font Lock machinery. But if the mode does not use
the normal Font Lock machinery, it should not set the variable
-@code{font-lock-defaults}.
+@code{font-lock-defaults}. In this case the @code{face} property will
+not be overriden, so using the @code{face} property could work too.
+However, using @code{font-lock-face} is generally preferable as it
+allows the user to control the fontification by toggling
+@code{font-lock-mode}, and lets the code work regardless of whether
+the mode uses Font Lock machinery or not.
@node Faces for Font Lock
@subsection Faces for Font Lock