Yea this is most laid back racing event I have ever been to.
From what it says on their facebook they will be leaving the back gate open so you should be able to come and go as you please.
Ever want to feel the difference in Z as opposed to an STI or a 300hp MR2 they let you ride shotgun with whoever you want (obviously if the driver approves). I thought that was pretty cool. I noticed I could barrel through the corners better then an STI but the STI can blast out of them so fast. It is one hell of a good time.