Avoiding action whilst towing up a glider....
Three times, over my career.
During a gliding competition, flown at Weston on the Green (the parachutists had gone away for the 9 days), towing up a ASW19 flown by a young naval pilot, - and the comp had been notammed - observed heading directly toward us, a twin out of Oxford Kidlington. So I turned right.
And the twin turned left. Thanks a bunch! All I could do now was dive, with the glider on tow. YOU DO NOT LET GO, because then there would be three separate aircraft dodging each other. The Navy pilot hung on boldly, he said later while making his witness statement, that he wanted full value of his 2,000 tow! In this case, the separation may have been 200 feet vertical, and if anybody had been watching on radar, we would definitely have blended on the screen. My main reaction was anger.
Another time, I saw the other aircraft at our altitude, heading directly for us, he saw us when I turned right, and did the correct action....nevertheless the following week I was able to locate and talk to the PIC, who had been occupied supervising a learner under the hood.
And can you beat it, on the third occasion, the opposition once again was supervising a learner under the hood, never saw us at all, and after we discovered who it was, lied about it. Of course, my witness was again the glider on tow, in fact this time the glider saved our bacon, because he saw the other guy and told me about it on the radio. I still couldn't see the other aircraft, so the glider pilot said, very very firmly, Turn RIGHT, NOW!!!!
Which I did. That time my knees did turn to jelly afterward. The glider pilot told me later that he had been planning what to do after the collision.