This news article is offering statistics on the capability of people in the community to detect forged passports. It is stated that 68% are unable to correctly identify a fraudulent passport (based on a survey of 1013 people).
The full nature of the testing is not described, but it is a statistic nonetheless.
Also in this article is a UK Home Office guide to detecting fraudulent passports ( and other identity documents). All of the suggested 8 suggestions are worthwhile, however we note that some basic knowledge of passport production and security features is required for these to be effective.
This, IMHO, is one of the major gaps in the use of identity documents outside of the border control environment. Where industries, be it financial or other, rely on identity documents for verification in conducting business, the base knowledge level on how passport security features operate is required for all employees who see these documents.
Failure to skill staff in this area is leaving a gap that can be, and is, exploited.