Here's the original thread on this RotJ cut scene:
http://originaltrilogy.com/forum/topic.cfm/Return-of-the-Jedi-cut-scene/topic/11816/
the restoration you linked too is nice to be aware of.
but to keep my theory going:
and to nitpick, there's only been 5 Star Wars celebrations (over 10 years), so calling it 'a star wars convention' seems a little understated. and the cracking down thing is no longer happening, as you can tell from the link you posted which is over a month old.