I just realized that when I place a form tag on my layout page, surrounding the RenderBody section, the unobtrusive validation is not being generated. Something like this:>
I've just run into the same problem, but possibly a better solution based on Darin Dimitrov's answer.
The trick is to create a page base type, based on the WebViewPage
abstract public class FormFixWebViewPage : FormFixWebViewPage
And then in the Web.config file under the ~/Views/ folder, alter the pageBaseType attribute under pages element, which can be found in the system.web.webPages.razor section: