Tortoise, that's a load of shit. If someone in a mask with superhuman strength kills four peopel in a city and there are two people with superhuman strength in the region at the time, you can damn well bet that'll help solve a crime. The only way the list won't help is if you catch him or her red handed at the time, which doesn't happen in most crimes. Criminals are usually caught after the fact or in stings, situations for which lists would quite useful.
And? If a person is a superhuman, of the type you reffered to in the "trail of carnage" model, the fact that the cops know who the criminal is, is irrelevant. They cant bring him to justice. SImply put, if he is so dangerous to society that he needs to be put on a list, what the hell is the use of knowing who he is? The cops cant do anything. So what is the benefit? SUrely he will leave evidence at the scene in the form of DNA, or fibers. Or then there is good old fashioned police work. You know, who would have a motive to kill those four people. They will have to do all of the above just to get an indictment on the charges.
Simply put, and I will go into exhaustive if somewhat poorly organized detail, the cost of enforcing the registration, and keeping up the beurocracy which maintains it, will not be outweighed by the very few crimes it helps solve. It would be more cost effective to just spend the extra man hours on the police forces to identify the criminals in standard ways.
Of course then there is the fact that when people snap, they tend to do so in places where they are familiar, you know, like school, or the post office. This means people will recognize them. "Oh God... he was wearing a mask but I knew it was Marty! I recognized his voice and his chizled superstrength chest!"
If it's domestic, the list doesnt help for shit, because people the victim knows are automatically suspects. "Well Jim, the ME said it would take someone with enough strength to swing a train like a tennis racket to do that to Mrs. McKinnes' face"
"Wasnt there a guy holding up a truck when we got there?"
"Yeah"
If it is a moustache twirling supervillian or supergang member, my argument holds without me elaborating further, because they WONT GET ON THE LIST. Sort of like how most homicides are commited with unregistered firearms last I checked.
In fact, lets take a look at most crimes.
WHite collar crime: Stuff like embezlement, fraud, etc. There is no way to know if the person involved had superpowers. List=useless.
Various forms of larceny, arson etc: No way to know. List=useless.
Violent crimes
Now we may be getting somewhere. But if the mutant doesnt use his power in the commision of the crime, the list is useless.
lets start with murder and work out way down
Gangland warfare: culprits known
Serial killers: No way to know about powers until after the guy is caught
Domestic: culprit known or found with policework. If the husband can shoot lasers from his eyes and lasers were the murder weapon... yeah
Killer for hire:A smart assassin will not use his his power, or will have a power which is unknowable.
Random snap: MIGHT be useful, depending on the nature of the snap and the power used. But these are rare occurences and when someone snaps, there is not typically any doubt about who the culprit is, even if they do wear a mask.
Felony Murder: Depends. But typically I dont suspect the list will be useful, as people who kill in the commision of another felony are often criminals and would thus almost by definition not be on the list.
Rape and molestation:
Good luck getting it reported
Serial rapists: unless the power is used in the commission of the crime, which it probably wouldnt be because serial rapists are like serial killers in their lack of sloppyness, there is no way the list will be useful in the vast vast majority of cases.
Date Rape: Little doubt exists as to the identity of the culprit. List is useless.
Random power/control rape: these cases are rarely even reported, let alone solved. But unless the perp used his power in the commission of the crime, and the victim knew it, there is no way the list will be informative
Armed robbery: Maybe if the perp used his power. Armed robbery may be the only case where a superhero list may be informative. But these are usually solved by brute police work anyway
Assault: The victim typically knows the attacker, or could identify them.
I really am not seeing how the benefit outweighs the risk
Your arguement relies on the assumption that 1) they'll be sloppy 2) the cost of any errors is greater than the benefits of keeping a list.
Look Cat, someone can steal my identity for what... 15 USD, by walking down to the county clerks office and getting ALL my personal records. ALL OF THEM. Address, phone number, moms maiden name. All of it. SO forgive me if I dont have much confidence in government to keep my private info private.
Keeping that list confidential will fail for the same reason staying conspiracy theories are all bunk. Someone will eventually talk. A disaffected employee will leak the list, a Stormfront.org racist bigot will hack the list. No matter how hard you try, a centralized database (which is the only way such registration could ever be useful to law enforcement) WILL be hacked eventually. Or portions of it will be. It is not a matter of sloppyness.
Second, I do content that the risks associated with maintaining a list of non-criminal supers would in fact outweigh the benefit. And it just so happens that I have all of human history backing me up.
The first or second wave of supercrime from the local supergangs will spark public outcry. Afterall, what good is the list if they dont use it? This will spark a series of legistlative efforts limiting the listed supers in order to appease the frightened public. But how will it be enforced? The list of course. Their will have to be some sort of recipt afterall. You know, to prove you registered. So what kind of laws will we be looking at?
Well what is one of the first things municipalities do to curb crime by a specific group of people? Curfews! They do it with teens, why not mutants? Restrict their freedom to travel at certain times and the politicians get to look tough on mutant crime.
Well, after that doesnt work, more stringent restrictions will be placed. Travel restrictions, monitoring devices, perhaps? The list is not informative for law enforcement but in the most outside and narrow of cases. What else are they going to do with it? Maintain a giant beurocracy for no reason? No. They will create crimes for mutants to commit.
Comparing having the audacity to exist with a car, or being a doctor is a non-sequiter. They are just not comparable. The police can use your car registration to solve things like moving violations, and get a stolken car back to its owner. A doctor does need to certify that they are competant and good at what they do. In a case even resembing the real world, the cops will not be able to use a registry to help solve even most mutant-commited crimes! Let alone convict a mutant in a court free of kangaroos. Nor can they (mutants) be banned from existing if they are not very good at turning themselves invisible.