This arc looks somewhat dubious to me. Rules for pirates? Aren't pirates people who just rob other people? What kind of rules would they have, other than rules dictated by those who are stronger, and the balance of strenght shifts. By default I don't like artificial things like this. It would make sense if it was just a game with money and treasures as bets, like poker.

Even if Luffy lost and Zoro was chosen, according to these rules he would just have to swear loyalty to the foxy captain. But that's where the rules end. So, right after that oath, Zoro could chop his ugly head off his shoulders and return to Luffy's crew. End of story... I mean, loyalty among pirates? The only loyalty should be that among friends and comrades, like in Luffy's crew.

Well, hopefully there will be good fights, nonetheless.