Is the USCIS number (USCIS#) on a green card a sensitive piece of information? If so, why?
I see that some people blurry it, e.g.:
The blurred out number is known as the "A" number or Alien Registration number. It's a unique number that USCIS gives a noncitizen when he or she applies for a benefit, such as a green card.
A person's A-number is like a person's social security number. It is considered to be sensitive personally identifiable information, which is information that, alone or in conjunction with other information, can be traced to the identity of an individual.
The A-number is linked to a person's application(s) for immigration benefits. Some of the information that the U.S. government requires a noncitizen to disclose in such an application is private and sensitive information that could be used to cause further harm to the person. For example, an applicant for permanent residency must share identifying information such as his social security number and mother's maiden name, as well as information about his medical history and finances. If the A-number is compromised, a person's privacy is compromised, and the information disclosed may cause harm, if not embarrassment, to the person. The USCIS #/A-number is blurred in order to protect the privacy of the individual.