Prior threadAccepting that a decision
not to file a SAR must be documented, scenarios like yours are going to be drawn to the attention of third party reviewers. You simply cannot say "We didn't file the SAR because we knew it was worthless."
Your perp lacks some basic skills. Your SAR's only contribution to the realities of law enforcement will be a bogus e-mail address. If you can enhance it with an ISP, its value increases, but not to the point where it would be measurable.