From memory, STK 0.9.3 starts with a small number of tracks unlocked, which would have to be unlocked through Story Mode. However, none of the Grand Prix sets were unlocked.
I think that every single game type and mode should have at least one option unlocked by default. For example, if someone wanted to download the game onto a friend's computer to demonstrate STK, they may not want to have to go through story mode or the add-on store before jumping straight into a series of races.
Do you think STK should start with at least one Grand Prix already unlocked?
PS. I guess a cheat to unlock all inbuilt levels could be useful for that scenario. I wouldn't be surprised if one already existed as a dev tool.