Does the USC 2257 Compliance Statement mean everything on the website is legal?

I wonder if the mere fact a ographic website or forum contains the compliance statement, which states all actors/actresses are over 18, guarantees that were not actually viewing anything illegal. And if it was illegal, could a user be penalized even though the website has the statement on its site. I ask this because sometimes some actresses can be dressed up to look young and its disturbing.