Not on ops, but remember an occasion on tankers when a newish captain appeared for pre-flight planning obviously still under the influence from the previous night's heavy session. His older rear crew all suggested that he might have a heavy cold and be unfit to fly, but he refused to take the hint. They then all unanimously declared themselves medically unfit to fly, and when this unheard of state of affairs came to the notice of the boss, said captain received what he later decribed as the bollocking of his life. It was all kept in house, the guy learned a valuable lesson and later became a highly respected tanker captain.
I suppose these days with everyone watching their own backs this wouldn't happen, but I know which approach I prefer.