I don't think most people are all that interested in how beer is categorised and I don't think it's all that important for us to educate them as to what beer falls into what category. If they ask, fine but there is no need to set out to teach people.
This event will have all sorts of beers available and people will be trying new things. If they don't come out of the event with a liking for craft beer, then nothing we can say will change that. Our job is simply to remind people that these beers are not just for festivals. At least one or two of these beers should be available in their local pub, all year round and if that isn't the case, maybe they should ask the publican why.