Yes, it would be very easy for someone to over run a school. Our local high school does have a plan for such a case. They won't tell the kids exactly what happens. But all I know is the school, will say code red and the school goes into lock down. When I was there in school. We used to practice like a fire drill. They would say cod red everyone stops what there doing and all the class room doors are locked, and if your in the hall way you get jerked into the nearest class room. We had it happend once for a real case when I was in the 11th graded when someone came into the school carrying a 9mm and refused to leave. I remember hearing all the doors slam shut and the 2 officers running down the hall way. There is a silent alarm in each class room just incase the attackers was in a certain class room they could let the police/main office know where the attacker is. A lot more to it to that. But for sercurity reason only the faculity knows. This plan has been in act since 1973 at the old high school. But only recently told the students so they know what code red means.