If you disconnect, you should be unkillable until you reconnect
Nothing irritates me more than when I'm trying to farm or get damage on a turret and all of a sudden my ping jumps to 10000+ and I get the "Attempting to reconnect" notification, than my connection stabilizes and I see my dead corpse because the enemy laner killed me when my connection went to hell. It doesn't really seem fair to me that your opponent gets free gold and a kill because of something you couldn't control. Only rarely do people have the heart not to kill you when you actually disconnect. I'm just tired of my opponents getting ahead even more than they already are when I disconnect.
I don't really see how this could be abused, so why can't Riot just make disconnected players unkillable? It seems like the fair thing to do.