Taint Mode Seems to be Ignored

Hello.  

Running Apache 2.2.12, mod_perl 2.0.4, perl 5.10.0, and CGI.pm 3.29.

I've noticed what seems to be a case of Taint mode being ignored with
respect to CGI params when running under mod_perl.

The following:

	#!/usr/bin/perl -T

	use strict;
	use warnings;

	$ENV{'PATH'} = "/bin:/usr/bin";
	#delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};

	use CGI;
	my $q = CGI->new;

	my $foo = $q->param('foo');

	open OF, "> /tmp/$foo";

	print OF "blah blah blah";
	close OF;

	print "Content-type: text/html\n\n";

	print "Taint: ${^TAINT}<br>";

	print "done<br>";

Behaves normally when run without mod_perl, i.e. it tosses 500 errors
and screams bloody murder.  However with the following setup: (only
relevant parts shown)

PerlTaintCheck	On
PerlWarn	On

<VirtualHost *:80>
	Alias	/cgi-bin/	/usr/lib/cgi-bin/

	<Directory /usr/lib/cgi-bin>
		Options	+ExecCGI -Multiviews
		
		SetHandler			perl-script
		PerlOptions			+ParseHeaders
		PerlResponseHandler		ModPerl::Registry
	</Directory>

</VirtualHost>

The cgi runs without error, opening files under /tmp based on CGI
parameter inputs.  The taint mode flag shows that taint mode is enabled,
and if $ENV{PATH} is not cleaned, it throws errors.  The behavior is the
same with both PerlTaintCheck On  and PerlSwitches -T.

What am I missing?  I have production code that is apparently not as
protected as I would like.

Thanks in advance.

-- 
-Nik