1) it doesn’t go as far back as you think. Only within my lifetime did the drinking age settle on 21. The Feds couldn’t do it directly, so they hacked highway funds. So that’s a bad example when porno has changed so much. What we’re risking here is parents who haven’t tried any solutions being convinced that litigation is the only way.

2+3. A simple cookie with a birth year ought to work. Why should every site worry about South Dakota’s definitions when checking a cookie seems reasonable effort. Circumvention of that is already fraud.