Mmm. I was once asked by my CFI to check out a 'hot shot' Australian pilot and show him round our circuit, as he was competing in the gliding championships which our club was hosting the following week. He was so far above me in the rankings that he was in the clouds, so I expected some really immaculate flying. We were in our T49 Capstan, a heavy side by side two seater, not noted for its aerobatic qualities. His flying was reasonable but his airmanship (look out, speed control on aerotow etc) was not, and I intended to get the CFI to fly with him as soon as we got back on the deck, as I felt I could not really let him loose based on his performance. Going round the circuit pattern on the downwind leg at 600ft he suddenly dived and did a loop which was the lowest I have ever done, and I was scared ****less. I didn't need to call the CFI's attention as he was at the launch point by the time we got there and had seen all this. I have no idea what was said to him, but he looked a bit abashed next time I saw him. He didn't do all that well in the comp either. I still look at that entry in my log book and shiver.