Not to defend the Feds, but, was this at an airshow with waivered airspace? If not, the Nanchang pilot goofed. During an airshow in waivered airspace, low passes are fine. At a non-waivered fly-in? Then a low pass could be seen by the Feds as a potential “careless and reckless” operation.
Low passes (and flying under bridges) are fun, but I don’t do them anymore. There are too many cameras everywhere with the evidence posted on YouTube. Also, I don’t understand all the teeth gnashing on this thread either; why all the bickering? She goofed, got caught, admitted to it. The FAA steps in... duh.