The homeless are a problem here in the greater Los Angeles area. End of last summer we were on a family bike ride making a bridge crossing by the river trail. There was a homeless woman at the far end of the bridge...mentally ill, on meth, or both. She was absolutely enraged at an A-frame road construction sign. Yelling at the sign, cursing, pacing around it, giving it the stink-eye, finally kicked it over and walked away shaking her head. All I could do was tell my kids "that is why you don't do drugs".
I make sure our bikes have lightweight XT derailleurs and aluminum nipples in the wheels but I carry a 2lbs spring baton. Go figure.....