Ovidiu: It was probably that I wanted to add several fields, not just the TOS that made use 'bad' search strings.
Zappoman; thank you, it's much easier to figure this out when you know what codes to play with. I'm posting the code I ended up with incase there are others who want a stricly php soluton to a TOS checkbox:
Add the following right after (About line 243)
<label for="signupuser"><?php _e('Just a username, please.') ?></label>
</p>
<?php //verify terms
if ( $errors->get_error_message('tos') ) {
print '<p class="error">';
} else {
print '<p>';
} ?>
<input id="tos" type="checkbox" name="tos" value="tos" />
<label for="tos">I have read the <a href="http://yourdomain.tld/tos/">Terms of use</a></label>
<?php //print error message
if ( $errmsg = $errors->get_error_message('tos') ) { ?>
<br /><strong><?php echo $errmsg ?></strong>
<?php } ?>
</p>
And then (just like zappoman said in his post) add the following code right after
extract($result);
(About line 260)
// check that the user checked the TOS
if ('tos' != $_POST['tos']) {
$em = "You must agree to the terms of use.";
$errors->add('tos', __($em));
}
This take care about the check for terms of service, but I'm still not sure how to create some function that check for age seperatly.
Any search I made on that just lead me chaptcha solution and the mature blog plugin.