My experience has been that while "all you care to eat" may be technically true, the practicality of getting more than one helping is much easier said than done.
Most CRT servers are motivated to get you in and out as fast as humanly possible. They get the same tip regardless of the quality of the service. And they get the same tip (from you) regardless of whether you eat one or five plates of food. Contrarily, the longer you stay at your table, the more the table is held up for the next party (fewer parties at the same table = fewer tips).
Therefore, the standard mode of operation of the average CRT server is take your order ASAP and then disappear shortly after your beverages and entrees come out. Then, as soon as the last princess has visited your table, the restaurant bus staff makes a swift and conspicuous effort to clear the tables around you. The overwhelming feeling you get at this point is - "okay, you've had your experience here, you've eaten some food, you've seen the princesses, now SCRAM."
So, in my experience, getting more than one serving at CRT involves: (1) having an extraordinary server (or being obnoxiously persistent in getting a server's attention following delivery of your first serving): and (2) being a fast enough eater than you're requesting the second serving well before the last princess comes to your table (because if you try to ask for more food any time later than that, your request will likely be met with great disdain).