Only in America..I'd sue the celebrity for millions and prosecute until my face turned red.
But in Japan, if the accident had happened to me, well first I'd ask my favorite idol for an autograph, and I wouldn't dare even thinking about prosecuting her anyway in fear of the backlash from the wotas and getting labeled as the most hated person in Japan by them...
so my point is basically, our dear Nacchi has nothing to worry about
