Yup this. I've been on open track sessions before, and you do get lots of hotheaded hatchbacks undertaking you on corners etc.
But Japfest was the first club session I'd been on, and the standard was amazing, everyone was respectful.
All you have to do, is if you see someone who wants to over take, LET HIM, slow down, let him pass, and then carry on having an awesome time!