It never fails that every few months you see on some forum about a guy using a classic "chase" system. They than give some stats and how they are 42-0 using it. Since I started in this business I would need a few more arms to count on my fingers how many of these "systems" I have seen. I would need some more arms after than to count all the people who are no longer posting these silly "can't lose" theories.
The "Due to Win theory" has sent more people to the poor house than the 1929 Stock Market Crash. One of my favorite lines of any handicapper is from Phil Steele and his famous "You can lose many times betting against a streak but only lose once betting on one." Just because a team has lost 5 in a row against the number does not mean they HAVE (due) to cover that sixth game. The Martingale System or any other system for progressive wagering whether used to play blackjack or bet on sports is doomed to fail.
A few years back I debated this during college football season and used the prior season as my starting point. The Baylor Bears dropped every single game against the number (w/ a push in the Tulsa game depending on your line) that year. How bad was Baylor? Plus 40 against Texas they lost 41-0. Plus 38 against Oklahoma they lost 9-49. Go back in time at the start of that season when they opened as a 7.5 point dog to Cal and were smoked 22-70. Being a $100 player you are now down $110 and figure they are due to rebound and will probably be getting great line value because of the blowout. So you double up and put $200 on their game against New Mexico getting 9.5 points and throw the remote into the TV when they get blanked 23-0. Outside of the push against Tulsa they go on to drop all remaining games against the line. Using the "due to win theory" and starting with the $100 and doubling after each loss, by the time the season finale ended with a 28-63 spanking at the hands of Oklahoma State you would have had to wager almost $57,000 using the double up theory on that final game (loss) just to win your $100 back. Being a $100 player by game six alone you had to put up over $3500. Granted Baylor is an extreme example, but that year 16 teams had ATS losing streaks of 5 or more with four teams dropping 7 or more in a row (7= $110, $220, $440, $880, $1760, $3520, $7070) with Iowa State dropping 10 and Illinois losing 9 straight against the number!
This is just one example I always use, but EVERY year in every sport you find cases like this (cough-cough, Detroit Tigers chasers).
So the next time the a "gambling expert" tries to persuade the masses about a "double up" theory, just smile and realize they will be broke soon enough!