In several FPS games, such as Team Fortress 2, there is this script in the "Killfeed" known as an assist.
If a player kills another player, but a teammate helps in that form, by dealing damage to the target, as well, he gets credit for it.
Adding this feature to Ace of Spades may help settle arguments in-game.
Dialogue without it sometimes goes like this:
"OMG, you stole my kill, you motherducker!"
"Dude, I did ALL the damage to him, and you shot ONE bullet, and killed him. You sack of schmitt."
"You're on a spree of only shooting one bullet for each kill! Your teammates do all the work!"
I've had dialogue like that in the game before.
But, with this, they can receive at least credit for the kill. Therefore, everyone's happy.
I hope I'm not a nuisance with my suggestion.