Why yes, but I know that a thong would also show through that tight a skirt,from personal experience. And I am not saying that a panty line got her kicked off the plane, but rather her attempts to avoid a panty line affected the way she dressed, either wearing a tiny thong/g string, which could be offensive considering how much we all got to see while she was on the Today Show or that she wore nothing at all. I am guessing that's why there was a problem.
If you've worn a thong, and something showed through a DENIM skirt, then I've got to get a refund on my x-ray vision glasses! You could wear a pair of boxer shorts under denim and they wouldn't show through.
At any rate, lingerie notwithstanding, I think this tramp got kicked off the plane because she was after her 15 minutes of fame. And by my count, she's already used up 14 1/2 of them.