I can see your point, Boost. It's a good defense. He didn't even know who this Luke Skywalker was, it was just a name...he didn't care anything about him. And while he considered Han a friend, he still probably didn't trust him completely. Top it off with the fact he had a reputation for getting into trouble, like with Jabba for instance. It's like, "What has Han gone and gotten himself into now?" Sometimes, friends like that you have to let fight their own battles or they'll take you down along with them.
And I have to admit, he did get choked pretty good by Chewie. But, I think BingoWings is also right when he says Lando probably felt a huge sense of personal responsibility when he saw how it all turned out.
So, that was a good anaylsis.
Seriously though, while I do think a Lando death would give ROTJ's ending more impact and if you take the psychology of the character into account, it would be justified to let him commit self-sacrifice to save his friends...I guess I'm forced to conclude based on the evidence that his guilt is called into question. What he did was a bad thing, knowing what we know...but, it's reasonable to assume he didn't realize what he was getting into at the time. If I was a jury member, you probably would have swayed me, Boost. :) You're like Lando's Johnny Cochran! LOL! "If the glove don't fit...you must acquit."
SAVE LANDO! :-D LOL!