Christine, I think it's just that there are SO MANY forgeries out there, that people are highly skeptical of any piece that shows up, especially one that sold so inexpensively. But you have to remember that the gal that sold this piece thought it was "carnival glass" and had no clue about ANY of the items she was selling since they weren't hers. She had quite a large set of Waterford crystal that she said was Fostoria, for example. I've been buying/selling glass long enough to be super suspicious of most "too good to be true" pieces, but this one rings true to me.
But I still won't sell it as Tiffany until I'm completely certain.