Secret agent at the Insafe seminar

I had an opportunity to join Insafe seminar at the Save the Children association's Tiukula house today. Insafe is a European Commission funded project to promote Internet safety and to help parents and teachers guide children in safe exploration of the web. What I learned is that currently there are no best practise examples on setting guidelines to online services (in any country). There are both techical and operational issues to be dealth with. Habbo and Finnish Irc-gallery shared their "safe internet" recipes but to be honest, there are still many issues to consider. I know that Habbo has done great deal to come up with good practises and satisfactory rules but unfortunately too often one has to learn things the hard way.

My suggestions:
a) To use a mobile phone to figure out the age of the user (after log in at the Internet one would get a password to her/his mobile phone). At least in Finland almost every teen has a mobile phone. That would also make it a bit easier to contact the parents if needed as mobile phone subscription is done by the parents and also their name can be found from the subscription agreement. I don't know how realistic this is, but its one issue which came to my mind.
b) Use Amazon.com/huuto.net/ebay type of reputation mechanism.
c) 'Plussa card' for teens -- are there any? Perhaps Neocard? To link membership card to identify the users. Belgium had an youth electronic ID card experiment in 2005 but it failed.

Perhaps these ideas are a bit lame. I quess the seminar did the trick in any case: it made me to think about child protection from technical and operational viewpoints.