Silently block PM from bad user

[dreamflavor]

There is a user on my site that is sending out a PM to every user on my board advertising his site. I would like to stop him but if I ban him then he will just change his user name and IP. At least at this point I know his user name. If he changes it then I will be a step behind.

Is there a mod that will let me silently block his PMs. It would appear to him that his PM is sent but it would never be delivered. It would be in the bad user's sent box but never reach anyone else's inbox.

Thank you.

*Edit
I found a solution.

edit /includes/class_dm_pm.php

Find
// insert records for recipients

Before add
//do not send PMs from bad user
if ($fromuserid != 720)
{

Find
eval(fetch_email_phrases('pmboxalmostfull', $touserinfo['languageid'], '', 'email'));
vbmail($touserinfo['email'], $emailsubject, $emailmessage, true);
}
}

Add after
}

If you have a better solution please post it but I think this will do the trick. The bad user will think he is sending PMs but no one will receive them.