I remember a case in the 1960s, in Czechoslovakia, when a local man went up for a ride in a Morava twin, attacked the pilot with a knife and asked him to fly him to West Germany.
The pilot did but the attacker ended up in jail - in Germany I think. I saw pictures of the plane afterwards; blood all over the panel.
These things happen once every so many years - nothing can be done about it. Extremely rare.