As it was stated before, a properly placed arb has zero risks: there is no way you can loose. However, errors sometimes do occur. Actually the human factor is the most important source of errors in arbitrage betting. One of the most common errors arbers make is they fail to place the bets correctly. You will be placing a high number of bets in a short period of time, and in the excitement of the action, it is not uncommon to make a mistake: you place your bet on the wrong team you don’t have enough money in one of your accounts to place a bet.

While errors have an important impact temporarily, on the long run your benefit depends on the odds. It may happen that by placing a wrong bet you will make a lot of money. However, bookies usually calculate the odds so they can make a profit, so it is not very likely that you will profit from these mistakes.

Bet cancellation is most feared by arbers. If you are betting on every possible outcome and one bookmaker cancels the bet for one outcome, you can find yourself in the risky position of betting. The cancelled bet can be repeated, but the odds may not be the same, so he can be forced to take a loss.

A bookie may be tempted to cancel the bid if there was an unintentional error made while quoting the odds. Bet cancellation may also happen if he reversed the odds by mistake. Many jurisdictions allow the cancellation of bets in the case of a “palpable error”: because there is no exact definition for this, the bookmaker can decide what “palpable error” is and what is not. If you see an obvious error, avoid betting: in 99% of all cases, these bets will be void by the bookmaker.

Capital diffusion can also cause problems: this is caused by the fact that it is very easy to deposit funds at many bookmakers, and it is very difficult to withdraw them. An arber can make profit only by spreading his money over many bookmakers so keeping track of the money can become a problem. It is advisable to keep exact records of every transaction made.

Bookies have different rules on certain sports, especially tennis matches. Arbing on matches with different rules can be profitable, but are extremely risky, so this is only for professionals who fully understand the risks involved. There are 4 tennis rules:

• Group1 (Ball Served) means the bet will stand if there was one serve in the match. So if there was one serve and one player retires, the bet stands with the bookie that has this rule.
• Group2 (1 Set Completed) means at least one set has to be completed in the match for the bet to stand. If a player retires after one completed set, the bet will stand. If there was no completed set, the bet is void and bettors get their money back.
• Group3 (2 Sets Completed) means at least two sets need to be completed in the match for the bet to stand.
• Group4 (Match Completed) means the entire match has to be completed in order for the bet to stand. If one player retires anytime during the match, the bet will be void.

Please remember that arbitration on matches with different rules can be profitable, but extremely risky: beginner arbers should not experiment with this.