If you have defined a bbcode like [yt]VIDEO_ID[/yt], you’re in trouble. Now your users can pass the new autoplay options calling [yt]VIDEO_ID&autoplay=1[/yt]. When you have 5 or more videos on a page, that’ s really a problem 
To avoid this just force autoplay to 0 when parsing your bbcode :
--- class_bbcode.php.orig 2011-02-14 03:05:22.000000000 -0300 +++ class_bbcode.php.fixed 2011-02-14 03:05:47.000000000 -0300 @@ -378,6 +378,9 @@ { global $html_allowed; + // Avoid autoplay on bbcodes + $text = preg_replace('/autoplay=1/i', 'autoplay=0', $text); + $this->options = array( 'do_html' => $do_html, 'do_smilies' => $do_smilies,
