Protecting wp-contact-form from spam

Ever since I installed WordPress on my (virtual) server, I’ve been using the WP Contact Form plugin to provide me with simple contact form. The plugin isn’t exactly under active development (Last Updated: 2009-8-28), but it got the job done and I was quite happy with it. Until spammers found the page and started abusing it, that is. There’s a bunch of other Contactform-plugins in the wordpress.org plugins repository, but most of them were either too feature-packed or development for them seemed to have stopped.
I considered adding ReCaptcha at first, but why would I want to put my visitors through such an ordeal; the captcha’s seem to have gotten very difficult to decipher.  Next possibility; implement Akismet (Mollom would have been a great choice as well)? There’s a great Akismet PHP5-class, you just provide your API-key and off you go. But it seemed kind of inefficient to have to do all that with the official Akismet-plugin already in place?
But wait a minute, why not just piggyback on the Akismet-plugin, as the Clean-contact plugin and wp-contactform-akismet did? Keep it simple stupid and so I just copy/pasted the clean_contact_akismet-function from Clean Contact’s code into my wp-content/plugins/wp-contact-form/wp-contactform.php and on line 142 I changed:

mail($recipient, $subject, $fullmsg, $headers);
$results = '<div style="font-weight: bold;">' . $success_msg . '</div>';
echo $results;

into:

$akismet=clean_contact_akismet($msg,$subject,$email,$name);
if (!$akismet) {
mail($recipient, $subject, $fullmsg, $headers);
$results = $success_msg;
} else {
$results = 'If it looks like spam and smells like spam, it must be spam. Leave (or rephrase)!';
}
echo '<div style="font-weight: bold;">'.$results.'</div>';

That was all it took to add Akismet spam-filtering to that KISS-y wp-contact-form plugin. I wonder why this isn’t in the plugin already?