Re: Overriding/Redefining a Non-Virtual Function in Derived Classes

In Scott Meyers' "Effective C++", item 36 states "Never redefine an
inherited non-virtual function". This admonition is repeated at
item 23.8 of C++ FAQ Lite ("[23.8] Should a derived class redefine
("override") a member function that is non-virtual in a base
class?" at
http://www.parashift.com/c++-faq-lite/strange-inheritance.html#faq-23.8
).

I only just now recognized that in the MFC framework, this is done
all the time. Particularly with respect to message handlers for
CWnd-derived classes, it's common to see code like:

BOOL CDerivedWnd::OnEraseBkgnd(CDC* pDC)
{
 // call base class function, which is not a virtual function
 CWnd::OnEraseBkgnd(pDC);
 // ... code specific to derived class
 return TRUE;
}

I recognize that MFC is not a paragon of C++ good-programming
practices. It is also my understanding that the programming of
message handlers for CWnd-derived classes was an attempt to *avoid*
virtual functions.

But given the fact that it is used so extensively by the MFC
framework, is it truly such a bad idea to override/redefine
non-virtual functions in derived classes? Is it truly something
that should be left to "experienced C++ programmers", as mentioned
in the C++ FAQ Lite?