Make users agree a disclaimer before entering a forum

[demoniavbh]

Well, I don't know if there would be an easy way to do it or if I should request a mod for this.

There could be inappropiate content for minors in only a particular subforum, and I'd like to restrict the access there in an easy way. So I though about making the users agree a text where they claim to be over 18 before entering THAT subforum, not the whole board.

I thought about writing a post with the disclaimer and whenever a user replies saying they're over 18, they have the access granted. Of course if the user posts anything else and you delete that post, the access is restrained again.

I don't know what would be the best way to do it or if that's even possible.