Add-on Specific Node Access Agreement

I may be going a bit mad, but I was sure there was an add-on that allowed the creation of an agreement specific to a node, that a user had to agree to before they could gain access. For example you could have an adult section where users had to agree they were an adult in their country before accessing in.

However I had searched all over but can't find it? Does anyone know if this actually exists, or have I indeed lost the plot?