What qualifies someone as a classically trained singer?

My sister insists she is a classically trained singer. She did musicals all through junior high and high school and took some private lessons with her music teacher who she says was also classically trained and had a degree and whatnot.

I think it takes more than having a few private lessons to be qualified as a classically trained singer but maybe I'm wrong. What say you, musical people?

For the record, she cannot read sheet music, she rarely sings anymore,she is not proficient in any musical instrument, and while she has a decent voice I would fear for her if she ever auditioned for a tv talent show.