Interesting book i own that goes into detail about a battle where U.S and German soldiers joined forces to rescue French VIP prisoners.
It doesn't really work that way. There is no price for being the person to be last for the longest time, it is about the person who posts last.
However, since there is unlikely to be a permanent last post (unless the forum were to shut down or other shenanigans), it comes down to who can maintain the last post for the longest time.