Asp.Net MVC Beta: Previous RouteData overrides current RouteData?

public ActionResult Details(int id)
    {
        var viewData = new DetailsViewData
        {
            Booth = BoothRepository.Find(id),
            Category = ItemType.HotBuy
        };
        return View(viewData);
    }

routes.MapRoute("shows","shows/{controller}/{action}/{id}", new {id = 0});

www.mysite.com/shows/Booth/Details/1  => Details(1)
www.mysite.com/shows/Booth/Details/2  => Details(1)  //from ModelState["id"]