So if an army marches across our border, terrorizing and killing American citizens, we should... what? Arrest them?
Look, we're both on the same side on this issue so don't get me wrong. Yes, if an army marched across the border killing American citizens then we would be justified in slaughtering them. No one is justified to start shooting illegal aliens unless actually threatened with bodily harm. This woman showed a great deal of restraint which was wise because if she had started shooting the news coming out of Cochise County would be very negative and she'd likely be in jail. As you can see, she was not harmed so for her to have started shooting would have been wrong. She didn't know that she wouldn't be harmed, but she took that chance and was right to not shoot.
Serve them tea! And I have these lovely cookies I just baked this afternoon. /sarcasm
Not before they are offered medical attention, food and water after which they are given a date to return for a meeting to voice their grievances ;-)