Now when you say young winning, are you withdrawing your funds? Try to make a withdrawal and let us know from there. If you input 0.001BTC an win 1BTC but can never withdraw it then you didn't really 'win' anything now did you?
999Dice isn't scamming by blocking withdrawals. The only question is the provably fair system. I have cashed out 4+ BTC at once from 999 once. More than 1 BTC many times.
Edit: Though there's no certainty they would pay out big money. Just haven't heard of them refusing to pay.