I can't say for sure if Erika knew the full story around Tom's hijinks, but she definitely was aware that he was defaulting on loans. Knowing this she is spending, and spending, and spending and bragging about her XXpensive self. She thought she was titanium.
This from the Season 9 Reunion:
Erika’s happy to talk about Lisa Vanderpump all day, but when it comes to Tom [Girardi] defaulting on a $15 million loan, she doesn’t say a word,” Andy said.
“How ’bout this,” Erika shot back. “Resolved, and they apologized.”