manpages output: \n not escaped to \\n?

I'm finding in manpage output that text such as \t
is output as \\t (correct), but \n is output as \n
(that is, unchanged, and incorrect).

I look in manpages/params.xsl, where I find this:

   <!-- * now, we need to restore single-backslashes in all roff -->
   <!-- * requests (because the substitution above doubled them) -->
   <substitution oldstring="\\fB" newstring="\fB"/>
   <substitution oldstring="\\fI" newstring="\fI"/>
   <substitution oldstring="\\fR" newstring="\fR"/>
   <substitution oldstring="\\n" newstring="\n"/>

If I remove that last line, the output comes out
correctly as far as I can see (that is, \n is output
as \\n).  Comparing the old and new output for several
manpages, I can't find other effect.  But perhaps there is
a better fix for the problem?