Technically she didn't have a sign or banner nor did she use foul language or make an obscene gesture. Its in bad taste, yes, but you can't do a damn thing about it because bad taste isn't against the law.
If they kicked her out then they would of had to kick out every jackass Yank fan wearing a shirt that says:
We all know that everyone up there would freak if they had to do that.
There really isn't an issue here. Well, I take that back. There is one. The media obviously doesn't have anything better to write about.