I'm trying to avoid taking the piss and using Lambo's and Veyrons for a hatchback race. GT5 reminds me of GT2 where you could pretty much use anything in every race. The golf is a great idea though, may as well start a Golf collection going while I'm at it.
The cars don't have "flag" to tell the game if they are hatchbacks or not, so the event has no way of knowing if your car is one. It's the same with Compact Championship. Look at the restrictions for both events, the game simply doesn't care what you use. It's the honor system.
Actually if you click entry requirement(or something like that), and click the Garage button in there, it filters your garage list to the cars that eligible for the series. I think in European Hatch back the requirement was only European....I could've entered McLaren F1 if I wanted to....I guess its sorta a hatch back....