MY, my. What a frothing rage Ralph Pixton, MBE, - the definitive voice of RTHK - worked himself into on the air early yesterday morning. What brought about this burst of apoplexy in the otherwise serene Pixton countenance of a morning was the front page picture in yesterday's South China Morning Post which depicted an elderly woman picking up empty cans left littered by sports fans queuing in the background for Rugby Sevens tickets at Victoria Park. ''It's a disgrace,'' fumed Pixton. ''They should be ashamed.'' Though it would have helped if he had explained to us yawning listeners what exactly constituted this act of ''shame'' he was ranting and raving on about. But what a pity the veteran broadcaster didn't have the presence of mind to dash over to the record library and pick out a recording of Rule Britannia to provide background effect as he unleashed his furious tirade. That would have been a touch of theatre worthy of the moment.