Thing is whether it is piracy or not, FD has said killing for any reason or none at all is within the rules of the game. When you choose open you have to accept that as a possibility, even NPCs do it. To ungraceful exit is something that they said over a year and a half ago was an exploit.
But this conversation has gotten off track. This was a suggestion about making shadowban a true punishment for anything it is to be used for and not to argue just combat logging
Personally I think that FDs priority should be a complete rework of their netcode and networking setup. With the plans to have multi-crew I genuinely can not see it being anything else then catastrophe with miss-instancing rather then fun play in a group. All wings I've ever played with suffered from some missinstancing at some point and it is simply a complete joke that we are still on the same shady setup 2 years past release and FD is still advertising this game as MMO. So first point I would say should be rework of the Netcode to include server instancing and hosting when players play together or engage in battle. Before anybody shouts out about unbearable costs - Elderscrollsonline manages it on Buy to play/small cash shop and subscription option if you want to and it works fine for them as well as Guild Wars 2 being buy to play and then Cosmetic Store (which we have already, minus proper servers) So costs are not prohibitive unless you expect unreasonable reinvestable income for other projects.
Punishing loggers in more then just Shadowban should have been here from the beginning before Combat Logging became a play option. But I will whole heartedly support anything that affects combat loggers.
I also strongly agree that the 15 sec counter to exit is a joke. It should be indefinite if engaged in battle. Even NPCs have their right to kill