same-document references again

From http://www.gbiv.com/protocols/uri/rev-2002/rfc2396bis.html#same-document:

"Normalization of the base and target URIs prior to their comparison, as 
described in Section 6.2.2 and Section 6.2.3, is allowed but rarely performed 
in practice."

So, 6.2.4 (protocol-based normalization) is not allowed?

And no other forms of normalization besides those described are allowed?

Just checking.