A while ago, I went to an awards ceremony at BP ( not as recipient, but as a guest ) and noticed there wasn't a curtsey to be seen. One recipient was a duchess, who must have been a deb in her youth, and she must have been taught to curtsey. I came to the conclusion that the recipients, in the little chat they were given before the ceremony, must have been told not to try to curtsey.
Imagine the embarrassment if a woman falls over in front of the Queen.