I believe it to be pretty harsh when thinking about gliding competitions. How can it ever be a level playing field if say 5% of the grid would be prepared to take a cloud climb in order to fly across 'the big blue hole in the sky' to roar home and win the day?
Additionally, it's not really a problem in this country as we rarely get a (cu) cloudbase above 6000ft, however gliderpilots elsewhere have been wearing devices on the tip of a finger to measure the concentration of oxygen in the blood. On the principle that if they stay above about 95% they are fine to coninue climbing..... many of them upto 12500 even 14000ft.
I have recently done a hypobaric chamber run to these hights as an experiment. If something happens to cause stress and potentially hyperventilation (maybe you thought you saw another glider in the cloud), you feel all the symptoms of going hypoxic. I am sure the decision making process will be impared and the whole fact that you are up there without oxygen is highly dangerous!
As for competition, I believe there should be formal BGA training to fly in cloud, or all should be banned from doing so.
TBK