This IP manipulation would only work if the commander was in your instance shooting you and would be easily reportable if a commander has a series of kills from combat logging then you have evidence from player reports and bountys and combat logging wouldn't be very common because they know they will die anyway in 3mins plus there are suites of programs that can identify people cheating CSGO for example uses this tech
And let's face it the game is 100 times more reliable than what it once was I can play all day and not have a single disconect on the live game
Urm - what if someone, just for lulz, were to have another connection and use that to pop instance connections for the player filling his lulzbucket at the expense of those shooting at him/her/it? and mine their delicious rebuy salt?