I do understand the arguments about not giving the scammer tag because of being under legal pressure, however I think some are viewing the scammer tag the wrong way. The scammer tag is not "You need to do this even though it may or may not be illegal". It's not about about dealing justice, or punishing people, or forcing people to do anything. The scammer tag is "He made x agreement, he can't or won't keep it". It's a warning about those who make promises they can't keep, and there's a lot of those around here.
IMO a scammer tag pretty clearly fits the situation, on the other hand he's a longstanding member (year and a half), has fairly good rep, and this is his first and only real incident. Have there been other incidents? Does he have any other investments?
On the other hand giving a scammer tag to the one person that went into their own pocket to hire lawyers to try and sort out Nefario's mess (and in the process forced Nefario to give out those lists, because I don't think it would have happened otherwise) seems...perverse. Maybe it's just me.