From chatting to various people, mainly newcomers to the ISO or just new race meeting attendees, the reason they haven't attended before is that they think the racing is ultimately serious. They think they won't be welcomed into the class because they don't know every rule or they might get shouted at by the top guys because they were in the way etc. This is most definately NOT TRUE. The main thing the top guys want is more ISOs on the race course to race with. They will even be keen to try to help you go faster so that you provide more competition!