I have heard of two incidents in our troop involving boys being sent home from a camping trip:
One boy chasing another with an axe. (I was not told how close Scout A came to catching Scout B before the adults stepped in. My impression is that nobody really thought Scout A was actually intending to strike Scout B with the axe, but one does not need too much imagination to picture what could happen if Scout A, while running with the axe, happened to trip on a rock, resulting in a potentially very bad day for Scout B, or Scout A himself, or innocent bystanders C, D or E who happened to be standing in the wrong place at the wrong time.)
One 11-year-old Scout who was sitting across a mess hall table from an older Scout (15 or so) and the two were having a disagreement over something, and the new Scout decided the way to resolve the dispute was to take his fork (I think it was plastic but I am not certain) and stab the older Scout in the hand. With some force, so plastic or not, some blood was drawn, but there was no serious injury. The stabber's parents were "asked" to take him home and the troop ever heard from them again. (I heard this story in greater detail than the other one because the Star Witness for the Prosecution happened to be my son. He was sitting next to the older Scout trying to eat his breakfast when forks started flying.)
So I think it is fair to say that when a Scout is sent home from camp in our troop, it was really the only option under the circumstances.