I agree with Beverly. I wouldn't want to be forced to buy a kit if it's a whole project to finish. I'd want to buy my own. I've only taken one class and was fully prepared--bought all my fabric a couple weeks in advance of the class. Was really perturbed to have to wait while others were still shopping for fabric and the teacher waited for her! Time is money.
Having the kits included in the class fee would be my preference for a techniques class. It would simplify the teaching and eliminate the shopping (and the irritation that goes with waiting for someone to shop). That said, start on time every time. Reward the students who value everyone's time, not just their own.