Here's a thought.
Bring back follow.
Then use it to track the boxers (really not hard to do, just flag it).
Every time a boxer is confirmed simply Delete all the associated accounts permanently deny that IP address/addresses access to Bliz servers (also not hard I've seen it done on BGO on more than one occasion).
If the execution could be publicly announced as it happens that would be icing on the cake (maybe even a graphic for it).
Of course subscription rates may go up a tad to cover the overhead of the new employees but it would likely only be a couple of bucks.
if your using it legitimately and free of exploit your good. If your using it to solo Zerg well, unless you buy some new hardware and reroll your pretty much hosed.
Do you have any idea how many people buy RAF accounts and put themselves on follow and stuff? bgs or not its a big selling point for extra accounts.