Please do not take any notice of this guy, he clearly is not aware of the facts.
FACT, if the girl is 17 no such notice will save you.
Fact, if the girl did not sign a model release, no such notice will save you.
Fact, if the guy selling the content is not the owner, no such notice will save you.
Fact, if the police arrive at your door and start asking for the IDs of a model, no such notice will save you. They only have to say she's under age and you're going with them to jail if you can't produce the documents.
What if Ashhahahahaha decides the website is the primary producer of the website, banners and tours, etc.
Aslo what is sexually explicit is debateble, in court with you paying your lawyers.
Don't fuck around with your business, liberty and future. Just keep some records.