There IS software to link accounts based on personal information and determine possible alters in Second Life and other social platforms, but available to law enforcement and ethical hackers. Some programs are available to anyone willing to pay the license. If paying $2000 dollars is worth to you, check out Paterva's "Maltego".
In my personal experience, the griefers are alts of the same fruit cake. If vampires can (and do) have hundreds of alters to move up in hierarchy, you know there is no limit to how many alts a main account can have. Then something like Radegast allows them to pop at the same time, anywhere.
There are no huds that powerful, available in the marketplace, because of security issues. But everyday law enforcement personnel signs on to report and catch pedophiles and other scum. I have seen griefing reports closing multiple accounts of the same individual within a few hours, because he is on the FBI list. So, they are around...