"Chasing Madoff" was really very interesting, here's an interview with the guy who first proposed Bernie as a ponzi op:
http://youtu.be/cfwJ06hc0_8?t=4m48s (the whole thing's very interesting and relevant)
http://www.youtube.com/watch?v=s68FR1MXT8Q

But yes, I would've thought that due diligence requires any sensible investor to go over the steps outlined in here before handing someone any considerable amount of cash. It is almost certain that some of the deposit schemes on offer here are illegitimate.