Now I'm curious: what was in the watermark that would trigger Outlook? (I'm having some fun speculating. My guess right now is a ye olde "bu¥ vi@gr@ ch33p!!!!" spam trigger.)
No, it was a bit more subtle than that but I'm definitely not going to post the secret sauce in an open forum. The trick is to trigger the filters in a way that they'll block the mail completely, not just spam trap it.
