The easiest solution to combat logging is two fold. Make it where the logger's ship remains in space for 1 minute after the log. Also make it where the aggressive ship faces steep reputation loss and bounty penalties, and loses the ability to dock at stations for 15 minutes. Also, if they log during those 15 minutes after killing someone, their ship remains logged in with a beacon that points to their last known location.
Win-win for everyone, IMO
Useless. In a peer-to-peer network, with no way to determine where the disconnection occurred, this offers endless opportunities for abuse. It only requires minimal know-how to 'combat-log' another player from a server.