How is RedirectToRoute supposed to be used?

I have this in my Global.asax.cs:

routes.MapRoute("BetaAccess", "beta-access", new { controller = "Beta", action = "Index" });

And this in my controller (index action on HomeController) and it definitely is getting hit:

RedirectToRoute("BetaAccess");

But still no redirection happens... it just goes to the normal home page. Am I using it wrong?

Also, I can do Response.Redirect("~/beta-access") and it goes to the beta page...