We default the value to 20 as that comes from what Minfraud have suggested. The lower the number, the lower the risk tolerance and the more likely the Minfraud checks will fail a Payment. The higher the score, the higher your risk tolerance is and the more likely a transaction will be accepted.
Please see MaxMind Minfraud for some details about how the scoring works - please also go into the learn more on the Minfraud page. You may also wish to review their Understanding Risk Scoring page as well.
We have provided the ability for your organisation to change these values up or down. This will depend on the level of risk your organisation wishes to take and that is for you to determine. See the MinFraud Set Thresholds for the Risk Score for some guidance.
Minfraud is included as part of Payments2Us and provides an important role as one of the methods used to avoid fraud and card testing.
We have added Minfraud protection for a good reason. It is not our recommendation to disable.
However, if you wish to disable, set the Minfraud Scores to blank or 0 (zero) on the Merchant Facility.
We do not recommend disabling Minfraud. It is an important security check. There are a lot of other checks as well and this is just one component.
You'll see some links and references in the What should we set the Minfraud Value to? as to how the risk scoring works. At a high level it checks the data entered to see if all all matches and makes sense. This means, even if someone were to complete Captcha's successfully, they still could be pick up as fraudulent.
The risk of disabling is card testing or fraudulent transactions could be completed on your payment form.