The law eliminating citizen's arrest in NC only changed a few years ago. Citizens still have the power to detain as I mentiioned before so I suppose the only difference is that a "citizen" cannot transport the detainee from the scene. I do know the new law only gives you power to detain someone until the police arrive. As I said earlier any citizen becomes an instant officer when they are assisting a sworn officer. Also a sheriff has the power to deputize anyone which I suppose would constitute the "posse" you mention. The power to arrest comes from state statute and the good folks in Raleigh obviously don't think it's a good idea for everyone to have that authority. Sorry I do not have the exact date of the change. My dial up makes looking up general statutes a pain in the butt.