When your CIS, CRM, Campaign System, or Call Center system fails to find a customer record that exist, you have an unhappy customer, or a lost opportunity to make profit. In this case, failing to find records that are present has a relatively small penalty.
Software that is good enough for "Duplicate Discovery" in marketing systems, or data warehousing systems will frequently leave undiscovered duplicates in the system the penalty is small enough for organizations to tolerate some failure.
When an insurance company fails to find out that it is doing business with a known perpetrator of fraud; when a Government welfare agency fails to discover that an address has been used for multiple fraudulent welfare applications; when a police officer fails to find out that the person in the car he/she just stopped is a serious threat, the penalties are likely to be large.