Yeah, I thought about the "bet everything each time until you lose" approach, but I am not sure I would qualify that as a betting system.
Years ago when Party Casino had a weird bug I used martigaling, but that fit the bug which was the following:
- They gave you a free bonus (ie you use their money) of for instance $100
- You cannot cash out any of that money until you complete the wagering (usually 100x)
- However, if your balance was above the bonus amount at the end of every bet, and you left the table then rejoined - all the extra above the $100 in this case became real money.
Thus if you bet $1 and won $1 on the first hand of blackjack, then left the game, you would now have $100 that was still restricted and $1 that was actual available cash in your account (to use, withdraw etc).
I usually did a $2/5/10/25 type system or sometimes a more conventional 1/2/4/8 type system, and back in those days these casino bonuses were pretty common (the money was not available for use at the poker tables), so it was a nice risk free way to make some extra money, but that was due to a flaw in how they handled money won at the tables.
Note, if you sat with $100 restricted and won say $5 and stayed on the table then lost $5 you would lose the unrestricted (if you had left the table) money first, so it was always correct to close the game whenever you were ahead, get the real money, and go back.
I probably did a hundred of those or more over the years before they fixed that, and I am not sure if I ever actually cleared the wagering to get the restricted money
.