Sure it's possible. But, given that he hadn't commented or submitted on HN in 20+ days 'til now, it just seemed unlikely that he's currently actively delving in

Sure it's possible. But, given that he hadn't commented or submitted on HN in 20+ days 'til now, it just seemed unlikely that he's currently actively delving into submissions/comments to the extent that he'd catch this so quickly. So, I just found it not so much an "Aha! Busted!" moment, as much as it was noteworthy.