Sweepstakes, run properly.
Enter a contest with friends, watch the draw, and get paid out to the penny. Every entry, every prize and every penny recorded in a ledger that has to balance.
One pot, one ledger
Entries go into a contest pot that has to reach zero when prizes are paid. If it does not, the settlement is rejected.
Controls that bind
Deposit, spend and loss limits are checked inside the same transaction as the money. A limit you tighten applies at once; one you raise waits 24 hours.
A break you can take
Take a timeout or self-exclude at any time. Your balance stays withdrawable throughout.