Feedback module block doesn't follow visibility rules
Wow.  It's pretty snarky, for no better word, and does the following...

/**
 * Implementation of hook_footer().
 */
function feedback_footer($main = 0) {
  if (user_access('access feedback form') &amp;&amp; $_GET['q'] != 'admin/reports/feedback') {
    $block = (object)module_invoke('feedback', 'block', 'view', 'form');
    $block-&gt;module = 'feedback';
    $block-&gt;delta = 'form';
    $block-&gt;region = 'footer';
    return theme('block', $block);
  }
}


...which basically puts it on every page except admin/reports/feedback by stuffing the form into page.tpl's $closure variable.

So, yes, it does appear to ignore standard block visibility rules somewhat on purpose.