No, sorry, didn't mean to imply that, M-J. I wish I had been. Merely that I remember the build up to it on the news during that day and listened to it on the radio (as no doubt many here did). I discovered a few years years later that my wife-to-be had been there in the Arena that night and got a first hand account of it from her. There were all sorts of rumours going around about what might happen, including stories of possible dramatic defections either from members of the orchestra or by Rostropovich. The assumption at the time I think (and this was in the media too) was that the large number of 'minders' that were blatantly packing the seats at the side of the stage, and the strict shepherding into coaches before and after, were partly there to prevent that. Strange times.
One thing I do know that was clear immediately to those in the hall was that Rostropovich was very deliberately signalling exactly what that programme described. It wasn't any sort of myth that has been added to with hindsight.
(I did go to the Prom the night before but that doesn't count does it I seem to specialise in just missing historic events.)