HOMESTEAD, Fla. (CBSMiami.com) – First Lady Michelle Obama and Dr. Jill Biden appeared at the Ford 400 Sunday to serve as grand marshals for the race to honor military troops and families.

But, instead of a warm welcome to show support for the troops; the first and second lady were met with a chorus of both cheers and boos.

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“I was just terribly embarrassed,” said Bernadette Morris, the owner of Sonshine Communications, a marketing firm in North Miami. “I was embarrassed because this was the first lady of the United States of America and there is an office that she holds as the first lady and the protocol says we are to respect those that are in higher office.”

NASCAR fans are traditionally very conservative, but often First ladies are cheered despite the popularity or unpopularity of their president husbands.

The duo has faced the wrath of fans before. During the 2011 World Series, Michelle Obama was booed by some fans in St. Louis.

Morris, an African-American, said while she believes some of the booing might have had political contexts, she has other concerns as well.

“Though I dare to hope that it isn’t the case, there’s always the racial disparities,” she said.  “In particular as it relates to NASCAR, there are racial disparities.”

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Sunday’s incident at the big race could set back NASCAR’s efforts to diversify significantly.

“Well whatever they did to move forward, they have just been pushed back tremendously,” said Morris. “I would say ten steps forward and probably a hundred and ten steps backwards and they’ve got to start all over. They’ve got to really look at what they’ve done. They’ve got to analyze their marketing strategy.”

But some race fans still lingering outside of the track on Monday disagree.

“You know, I just think there’s a lot of people out of work,” said Chris Alexander, a race fan. “It’s difficult economic times. I don’t think it’s a racial thing.”

Regardless of its context, race fans Sunshine McQuown and Jack Storrs said it should have never happened.

“Very rude, yes very rude,” they said. “They should show some respect whether they like her husband as president or not.”

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CBS4 News requested an interview with NASCAR officials. They declined and sent a statement that did not address the subject of the story.