Sheehan was escorted back out of the chamber a short time later and there were unconfirmed reports that she had been arrested.
Boo-hoo. :)
FOX News just before the start of the SOU did say Sheehan was led away in hadcuffs, after trying to unfold a banner that was on her lap.
Sheehan was detained, according to Pacifica Radio, for displaying a t-shirt (which she apparently was wearing) bearing a political message (the Iraq body count).