I tried for SanJose95, Munich97, LA98 to get multicast feeds.
In the case of IETF 39 (Munich), I actually started trying at the previous
IETF in Memphis. I have never succeeded in getting a feed.
I've been to most of the IETFs over the past 10 years, so I have rarely
needed one for that reason. But I have also experienced difficulty
getting multicast feeds.
Perhaps there is another hidden message here - if you want to be able
to access an IETF meeting remotely, you're probably going to need to
make some advance preparation. e.g. installing the necessary tools,
arranging for a multicast feed, etc. Otherwise you're going to end up
trying to debug the problem while the meeting is taking place.
perhaps the meeting announcements should make this clear, and have
pointers to not only the tools you will need to participate remotely,
but also pointers to test cases (so you can tell whether things are
working).
Keith