Limey McLimerton

This would be disastrous. While I understand how frustrating it is to have a ship ninja-capped out from under you when you did all the work to make it cappable in the first place by somebody who entered the battle late and ignore your polite and courteous requests that they let you have your prize, there are also many other time where you get dragged into a battle as you were just passing through by some player who would never have had a chance to cap the ship, and you take it for yourself. If somebody pulls me into a trader battle by mistake and apologizes, I'll happily stay there and do everything I can to help them cap it. On the other hand, when I get pulled into a battle by somebody who curses at me, and threatens to shoot me, you bet I'm going to take that trader. The potential for players to abuse bans for ninja-capping is worse that the ninja-capping itself. The same thing has been happening in MMORPGs since the genre was formed. People fight over resources. Traders are the ore deposits of NA. Just because you see one first, and yell dibs in chat doesn't mean you get to have it. While it's rude to run in there and take it when somebody kindly asks you not to, it should NEVER be a punishable offense. Seeing as we're playing a game with open world PVP where ganking and seal clubbing is considered a game mechanic, why would this be a problem?

Windward, because sheeps.

Actually, yes they should. If you both own your own copies of the game, you can actually play together as well. I'm guessing in your case you only have one computer capable of playing the game, so that's not a selling point for you personally. As somebody who has spent years as an in game GM for several different games, I can't even begin to tell you how many times I've heard 'oh but my son/daughter/brother/etc was playing on my account' in cases of cheating/hacking/etc. I'm not saying that you're saying "oh it's for my brother" isn't true, but that excuse will get used 24/7 by crossteamers, and you know it. Buy two copies. Support the devs.

Death by snow-snow?

I hate you. <3