I am assuming you are referring to flying airplanes at an airshow. The answer is yes, it is worth it. Airplanes fly and people love to see it. If you buy a ticket to any sporting event you run the risk of being injured. For example; a broken bat, errant hockey puck, a race car crash with flying debris, etc. In the U.S. airshows have strict rules that must be followed regarding the line of flight of the aircraft and distance from the crowd. I am sure there are similar rules in the UK, because Europe is all about aviation rules. However, the risk of injury is always present in any facet of aviation. Do we ban car races because a bystander was killed by a racing accident? Nope, we don't.