Wading back into politics (in contradiction of my new, yet unstated policy) for a moment, why not get a warrant? The legal justification for warrantless wiretaps of U.S. persons is crap and clearly so. But that ignores the question of why bother? You can tap-for-free for 3 days before getting a warrant. And it's not like getting a warrant is hard under FISA. So I'm left scratching my head, asking why.
Of course, the maxim to never suppose actual malice when mere incompetence is a sufficient explanation probably holds.