You can lose your position on the leaderboard, though. There are still a few more days for people to pass you and then you would only win .1 BTC.
That's highly unlikely to happen. At my current position, 0.15BTC is a given. Even in the worst case, I'd fall to 0.1 and the principal amount is guaranteed.
All it takes is a leap of faith and lending hand I suppose.
Why don't you approach family? They must have $100 in their collective means. Esp if it is guaranteed.