The worst and somewhat classical incidents i have seen when marshalling were.
1) This kid of about 14 was trying to cross the little bridge over a river on the site. All of a sudden about two thirds of the opposing team opened up on him from a trench. In blind panic he took off running toward the opposite side and ran head first into the barrier across the bridge, knocking himself out cold.
2) This guy in his mid 20's was trying to assault the trench in the sites signature game (Trench). So under cover of smoke he goes running forward, leaps the sandbags at the front and promptly realises his mistake as he drops 8 foot down the other side into the trench. We all heard the crack when he landed and his scream as he broke his ankle on impact.
They are about the worst...but then theres always the high jinks that made the job funny...things like smoke grenades under the porta loo when the head marshall/owner were in it. Booby trapping the bridge for the first game so the lead marshall got plastered with a paint mine. Then the stanger things like lying down on a fox hole and sunbathing in the middle of a fire fight...Ah marshalling the best job in the world.