My son, who very diligently straps the Wii remote and tethers it to his wrist, was overzealous in bowling. Instead of letting go of the B button, he let go of the remote altogether, and the remote swung up and bapped him on the head. The battery cover popped off and batteries flew all over the room (fortunately nothing hit the TV or picture window).
A cautionary tale! He's banned from bowling for now (never thought I'd type that). Zelda and even Wario seem much safer than Psycho Bowling.