Assuming Google was ok for the deal they could have sold 100% of the company against cash or maybe Google stocks. Instead they sold I think only 5% during the IPO. Right now the CEO cannot sell more of his shares until May 2012 (http://ipo.nasdaq.com/Fundamentals.asp?cikid=826818&fnid...).
May 2012 $15.00 puts are $2.10/share, so at the current market price the insiders are still ahead. They may put a premium on diversification, but they also sold stock before the IPO.