Another Star Wars mystery I forgot to ask before:
According to Lando, Darth Vader and his peeps arrived before Han and Leia did. So when Han, Leia, and Chewie arrive on Bespin, Lando greets them enthusiastically, gives Han a hug, talks about his supply problems, hits on Leia a couple of times, gives them a room to hang out in, and then invites them for lunch. All the time, he is getting ready to hand them over to Vader, but he never hints that there's anything going on, or even acts strangely. For someone with "no love for the Empire", he certainly acts convincing when he's about to turn his friend over to them.