I've been thinking about this. I teach in a public high school. I'm a big guy, the size of the average barn door. Not fat. Big! I carry an old, hard-sided brief case to and from school and it is near in my class room. I haven't weighed it, but I would guess it weighs 40 pounds. I have used it as a wedge to get through crowds, a shield when a student lunged at me in clas, and as a bettering ram. We are NOT allowed to touch our students even when they are out of hand: so the fellow who ended up running into my briefcase was very surprised. Instead of hitting nuts, he hit a brick wall.

All it is is an old leather brief case with square corners. Totally legal going through security. Does this give anyone ideas of how to defend oneself when necessary?