Totally agree with this. She wouldn't be able to bear being called the Prince's wife as SHE'S the star who gave up her "career" to be with this nobodyAs to her not coming, I don't think she was worried about the booing, after all the RF do get booed. I think it's the South Park fall out, she wouldn't bear being laughed at or ridiculed and I think it was very likely lots of people would have the SP cartoons of them on their faces.
I also think she wouldn't have been able to handle seeing the rest up on the balcony, the ladies in tiaras and everyone taking historical photos without her being centre stage. Her entire plan when she met Harry, completely backfired. You need talent or a nice personality to be loved. She has neither.