You know, this is something that I hadn't even considered before about the dangers of making kids authenticate themselves reliably in a place like MySpace, but it's the singlest best argument against mandating age verification:

We are at a roadblock because Internet-scale multi-factor authentication of children is simply unworkable from practical, operational, technological, and cost perspectives. Left with relatively weak password authentication, we must ask: how long will it take for a black market of "age verified" credentials to surface? How long until children begin to share or lose their "age verified" credentials? How long until child predators become skilled in guessing and phishing for children’s passwords? How long before enterprising children begin to sell their "age verified" credentials? In the frightening case where a child predator is also a parent of a young child, we must assume that the predators will use their children’s "age verified" credential. If failure rates are similar to adult username/password failure rates, we will not have solved the problem and added a tremendous expense and burden managing literally hundreds of millions of children’s usernames and passwords.

It makes sense when you think about it. By creating a "trusted environment" through these credentials, you would end up creating an environment where the prevailing assumption is that no one can really be a wolf in sheep's clothing because they have authenticated as a young person. Most parents would naturally assume that such an environment would be almost, if not completely, safe for their kids and young teens to participate in without any meaningful oversight, which would only further increase the danger that would come with spoofing credentials.

At a minimum, parents would run into the problem of their children and teens being more likely, not less likely, to reveal their personal information in such an environment. After all, why would they have any reason to doubt that the person they are talking to is who they say that they are based on the information provided to them? Take the dangers that come with divulging information on MySpace, and increase it by giving the predator the certainty of knowing that the person they are talking to is someone they would like to target, and that's a good picture of where these proposals would leave children and young teens.