When I worked for a tree company, the drivers would sometimes forget to disengage the PTO on the trucks before driving. Never mind that the PTO lever featured a humongous red knob and that we had installed the biggest red light we could find and set it up to flash insistently whenever the PTO was active. The PTO shaft is not balanced, and the usual result of a driver going too fast with PTO engaged was a thrown shaft - once it went right through the front of a Fiero, missing the driver by about six inches!

__________________
1984 300TD