I must say SW3, I am now a little intrigued by the motive of your (likely innocent) original post.
This is an old thread which has been thrashed to pieces, however there is still life in it yet. This coming to thought recently as a pilot was attempting to obtain a clearance. He eventually got there however in an unorthodox manner.
I believe a CTA Endorsement for the RAAus would be extremely benificial. I know there will be many 'Egos' for the want of a better word attack this so lets look at some cold hard facts.
So you heard a guy in his ultralight that asked for a clearance into CTA. Let's assume that he was not authorized to fly into CTA because of his unorthodox method of obtaining a clearance. (if he had a PPL he would have known what he was doing). Fair enough, you have then suggested that RAA should be able to get an endorsement for CTA operations, presumably so this guy may better know what he is doing next time?
This is the type of pilot that we don't want operating into CTA and you are supporting him to an extent. Why if he wasn't licensed to do so, did he try and enter, obviously not an emergency as he would have said so? Did he have a certified altimeter which he is required to do so under RAA regs, did he have the RAD43/47 done on his transponder? Don't forget, he is mixing it with RPT. Do you want him mixing it with airliners that your friends or family might be on?
On a side note, was speaking to an avionics guy recently. He was perplexed (and peeved off) at the number of RAA aircraft owners that believe that they don't have to have their transponders RAD checked every two years. GA does and RAA is not exempt. He cited a recent example where a newly built and purchased Aircraft was flown from Qld to Vic. The new transponder had not been checked and the pilot removed the unserviceable tag. On the way home in central NSW an airbus overhead had to perform a collision avoidance as the transponder was incorrectly reading over 30,000 ft. That is someone I don't want to share CTA with!