If two accounts are killing each other from the same IP address that's pretty easy to spot. So then the question is to what degree and how's that impacting the rest of the players.
Then you've got the shades/helpers from a different IP address. That's harder and would need some system in place such as you describe to flag the account.
Regardless, none of that should be automatic. Each should be reviewed by HTC and dealt with as they deem appropriate (loss of kills, points, perks, etc. would probably suffice).
Other than that, the perpetrators should be discovered and judged by the community after a traditially entertaining witch hunt.