While its often less than what you'd call normal people who go around on carnival type thing from location to location. Its still their livelyhood and if someone got seriously injured they'd be in trouble with police, had people died they'd be on the hook for a long jail term, most of them run fine. Considering the number of these fairs the very low injury rate shows most are competant. The thing is, as in any job you'll have crap people, considering the risk of flying off something at high speed its just not a needed risk to take. Its not like it can't happen at Alton Towers too, but I'd feel far safer that they were being checked much more thoroughly.
AS for claiming compensation, thats completely fine, it wasn't a potentially serious accident, it was an incredibly serious accident with a lucky outcome. The issue I have is claiming an injury when you don't have one, to me thats completely unacceptable and would just make you a scum sucking cheat. You can very much claim for negligance despite injury, theres no two ways about that. If there was infact negligance they should be done, just because they got lucky with the outcome shouldn't change that.