Gov't Needs Warrant to Search Email

Engadget reports that "the Sixth Circuit Court of Appeals ruled [on Monday] that the government must have a search warrant before it can obtain email from your provider. Specifically, the court held in U.S. v Warshak that "it would defy common sense to afford emails lesser Fourth Amendment protection" than traditional communications like phone calls and postal mail."

I wonder, is there any concern here for spam filtering? Some ISPs can clearly see into end user mailboxes and occasionally pull that data out for spam filter troubleshooting. Do they need to be concerned about doing so?