No idea, but to assume and insinuate that she was booed because they are racist or hicks or whatever negative assumptions people where stating in this thread because it was at a NASCAR event, says as much about those people as they said about those at the event.
Anyway, does she deserve respect just because of her husbands job?
Is respect not something earned, rather than expected.
And as some have said, political make up of the crowd could be the reason.
Personally I could not care less, she has no impact in my life or means nothing to me .... just another bag of flesh and bone like everyone else ........ but I respect peoples right to hold their own opinions and not be labelled racist because of them.