hmm, it certainly doesn't without a method like ```IRouteCollection BuildRouteCollection(RouteCollectionBuilderContext context);``` 
but the problem is as soon as we get there the usefulness of exposing the ```IRouteCollection``` as a property stops making any sense. Technically from the name it sounds more correct to do what you mentioned above ( a pass through method to add to route collection, and finally a ```BuildCollection``` to return one). I would actually like to stick with the name and introduce the add and build collection pattern. Let me know what you think.