I have been writing a fluent API using the Page model. I wanted to have a method on the page that ran some actions that caused a submit and redirection. I wanted the method on the WatiN Page to return the new (expected) page instance. This isn't possible because Page does not have access to the Browser instance it is tied to.
Exposing the browser instance as a property on Page would allow a method in Page to return Browser.Page<T>(); for the next/current expected page.