When one is a lurker, they're bound to notice other lurkers.

Being especially interested in the darker underside to the election, Henry had been placing himself in areas where trouble might arise. Not to fix some of it himself-- just to observe it, still getting a lay of a land, a feel for who might win the power struggle.

But there's no pretending he hasn't seen this man's face before at this particular cafe, or that having noticed him, the man wouldn't also recognize him. So, putting his book, he'd tilt a nod at Finnick in greeting-- an invitation, should he like some company for a few minutes. One he hoped seemed harmless enough.