Ah, talk about damage... my brother was test flying a 6 person turbo prop, which used av gas. He and 2 other guys were considering buying it. They had it filled with fuel while they were talking with the owner. As they were waiting for clearance at the end of the runway, the engine started running rough and then died. The fuel truck guy had filled it with jet A. Had they been cleared a few minutes earlier, which could have easily been the case, they would have been just airborne over a densely populated suburban area. They passed on the plane.