You misunderstand me BackPacker.
I was saying that all the pilots of powered aircraft on this website (whether PPL, ATPL, military etc) should easily be able to select a frequency and make a quick radio call while under pressure. The most obvious example would be selecting an appropriate frequency, such as 121.5, calling a Mayday while flying a forced landing pattern, under pressure and with a high rate of descent. No-one here would have had a licence issued if they couldn't do that.
Therefore, I suggest it's not too much to ask for the 250hr glider pilot to have selected the Full Sutton frequency, made a call similar to that in my last post, whilst flying a circuit to land. I was not saying he should have contacted 121.5, but that still would be better than nothing.