lol.. well there goes my theory that casascius was throwing out this little puzzle to demonstrate how easy and convenient it is to import the keys from paper wallets!
That's what I figured, too. I did a google search for "Plain Sight Bitcoin" and found
http://sprucecodes.com/ who cross-promotes the paper wallets heavily. SO SURE I was on the right track!
Ah well, kept me from cleaning the house for a few hours :-P.
Congrats to the skillful winner!