@Dave:
I think the letter is a great step forward and fully agree with your 'Don't fly the mic' comment which of course applies to any type of aircraft. I would also agree with MJ that it's more of a cultural problem than an ability one. I just thought that the phrase in question was a little strong in implying that there isn't much spare capacity for transmitting because of the peculiarities of glider flying. I'm a very average Joe glider pilot having scaled the dizzy ranks to a silver but I've never had a problem using the radio at any time so I think it's over egging it a bit to imply (and I may be reading it wrong) that gliders are a special case. Surely the bizzare maelstrom of machinery known as a helicopter shouldn't be transmitting at all if we're talking about spare capacity.