The safety rules as really arse backwards. Like you, I was amazed when I saw people out there in shorts and a t-shirt...their own choice I suppose, but all its going to take is one preventable incident of someone getting badly burned for the series to earn a bad name. Thankfully, that hasn't happened (knock on wood), but its racing and accidents do happen.
Also, some of the rules are pretty stupid...IE you can run a 1000hp GT-R in street class. I mean, sure its within the rules, but is it in the spirit of the class? Shouldn't street class be for street cars? And how one modification (like any aero mod in enthusiast or a new ECU) bumps you up to street, where you have cars like said 1000hp GT-R.