I'd understand her being escorted from the premises; however, the arrest simply means that "free speech" is dead in this Nation. Perhaps her son did die needlessly. Remember, Constitutional "free speech" is explicity for political redress.
If the woman became abusive toward security officers or the police, then she's on her own. If she made some unfortunate comments in front of an officer impacting on Bush's safety, they may have had no choice but to detain her. We probably don't know the whole story.