Just curious to see everyone's theories. Some think Vader was well aware that Obi-Wan was alive and/or that he was living on Tatooine. I personally don't buy it. Ani/Vader doesn't seem the type of person to leave his friends or enemies alone - if he knew Obi-Wan was still alive and possibly that he was looking after Luke, I can't see him staying away for the next 20 years - he'd be obsessed with Luke as the "last" member of his family. Most people think neither Palps nor Vader knew of Yoda's existence - I'm sure they wouldn't let The Big Cheese stick around on an acreage somewhere. Another question - if Vader did let Obi-Wan go, is there any way he could hide the knowledge from Palps? You'd think Palps would want Vader to kill his former Master - it would further tighten Palps' grip on his apprentice. So anyway, my theory is that neither Palps nor Vader know Yoda and Obi-Wan survive. But who knows?