Um, well, example.
You look in the options and see this:
Do you wish to enable This Example Mod? yes no
You look in the page source (or the product code) and see the name of this option is "example_mod_switch", or $vbulletin->options['example_mod_switch']
Then you plugin would just be something like:
PHP Code:
if ($styleid == x){
$vbulletin->options['example_mod_switch'] = 0;
}