Online casinos are goldmines for the books when people are on tilt at 2am with no games to chase on. I know this because i've been a poster boy for this in the past.
whenever you make a new account at a book go into the casino (blackjack). put 1% of your account for 15 bets. you will automatically be up. then go 2% for 10 bets. you will still be up, its programmed to let you win the first visit..............but then take the 15% bonus on your balance that you just made and get out, never go back they will be waiting for you