blacklist patterns not working?

I get lots of trackback spams nowadays. I've been trying to use Blacklist Patterns in typo admin to filter them but I can't get them to work.

For example to filter a trackback ping like this:

Blog Name: online-gambling-casino

Title: online-gambling-casino

Excerpt: He stops walking and looks ...

I tried using RegexPattern "[Cc]asino" and StringPattern "casino".

But it doesn't get filtered. Am I missing something, or does the Blacklist Patterns not work for trackbacks?

Best,

Dae San