[vbresults]

Your best bet is to check for a static IPs in config.php.

PHP Code:

if (in_array($_SERVER['REMOTE_ADDR'], array('1.2.3.4')) {
    $config['Misc']['debug'] = true;
} 


Replace 1.2.3.4 with your IP, and if you have more than one Admin, add their IP to the array.

There is no other reliable way IIRC -- someone correct me if I'm wrong.

I just looked at class_core and I'm almost positive the code Scanu provided does not work -- it is too late to change the variable at that point.