I'd like to take a minute to address your concerns.
First things first--I'm going to quote from our TOS
18 years and older
This website is intended solely for viewing by an adult audience. By continuing to view any material contained within this website, you are stating and acknowledging that: You are an adult over the age of 18. You will not allow anyone under the legal age of 18 to have any access to materials contained within. You are voluntarily continuing to view this site and will be exposed to material of an adult nature. If you are not comfortable with this, please close this page.
We expect all users to be in legal compliance. However, should the question of age arise, we will deal with the matter privately with the person in question. We hold our members to that compliance and we can and will request age verification documents if necessary. As it stands, there aren't any ways to verify a user's age through credit cards or any other way.
Any user found to be under 18 will have their account immediately disabled.
As for the flag suggestion, that's not a very good idea. There has already been abuse of the flags we have now and adding another will potentially lead to more abuse. If you suspect a user of being underage, please e-mail me at firstname.lastname@example.org m with all of the information you have (i.e. screen name, links) and I will investigate.
The staff and I appreciate your concern, but don't worry, we have this covered.