So, the Tor browser could be used to hack Torn. It would be harder to detect hacks. All you need to do is to make the Torn server look for Tor I.P. addresses. Here is a list of most Tor I.P. addresses to block:
http://torstatus.blutmagie.de/ip_list_all.php/Tor_ip_list_ALL.csv
Once this is done, here is a blocking code for Tor, or you could just detect if they are using Tor, and watch them.
$ips = explode("n", file_get_contents('/path/to/tor-ips.csv');
if (in_array($_SERVER['REMOTE_ADDR'], $ips)) {
echo 'Please do not use Tor to access this website.'; die;
}
This will make it harder for Tor users to access Torn.