Support for "ignoring Navigation Property"

I have asked [this question in SO](http://stackoverflow.com/questions/15708246/how-to-insert-an-object-with-navigation-property-using-dapper-rainbow) and got no answer. I have Googled and SOed the issue but could not find any article that shows me how to do it. I am currently using NHibernate and my class' current structure is supported just fine. But it's not supported in Dapper. You may read my SO question for details. 

In the end I ended up with the following using the code in my pull request:

    public class Product {
        public int Id {get;set;}
        public string Name {get;set;}
        [IgnoreProperty(true)]
        public ProductCategory Category {get;set;}
        public int CategoryId {get;set;} // I have to add this. I don't need this using NH
    }

This works for what I need although I prefer that I can control the "ignoring of fields" by code and not by configuration (attribute) - which would be a different approach but this solution works fine for now.

Please let me know if this won't break the core Dapper behavior and objective. And, if this already exists and I missed the part that tells me how to do this, please point me in the right direction. If this does not exists yet, may I ask why this is not part of the Dapper core?