By default now, Cake will automatically use the AppModel class and create a unique alias to a database table if it does not find the file. This means that if you have a table that follows the Cake conventions, needs no validation, and has no associations to other tables, you don't even have to create the model file any more. Woah, talk about a serious time saver in some cases.
He also mentions a gotcha to keep an eye out for - misspelling the model name when you use it. It'll definitely break things. You can find out more about models in CakePHP from this section in their manual, The Cookbook.