that is not true.It is not because you have the "proxy ip to real ip conversion" plugin installed that it will prevent all proxys.That plugin will only work if the proxy(s) used passes the appriciate variables
- $_SERVER['HTTP_X_FORWARDED_FOR']
- $_SERVER['HTTP_FROM']
- $_SERVER['REMOTE_ADDR'];
There are several sites on the net that publish large lists with so called "anonymous proxys" and that proxys do not pass the above listed variables so your detection plugin will fail.As mentioned before there is tor (firefox extension for anoymous browsing)The user might be on a connection with dynamically assigned ip address in that case a disconnect -> reconnect will give him a new ip address ....