Fun Fact: USPS prefers that the address is written in all caps. https://pe.usps.com/text/pub28/28c2_033.htm
So I bet there is some internal API that searches or something for an address with all caps.
So I bet there is some internal API that searches or something for an address with all caps.
In the address form, there is a field for PO Box. It is labeled "PO Box". One would assume you should type your PO Box number in this field, e.g. "1234". That is incorrect. You must enter the entire string "PO Box 1234". In a field that is already labeled "PO Box"
It's been a long time since I've had to look at it, but there is a Postal Addressing Standards document that covers all of the various use cases. It actually gets pretty interesting when you need to get a letter delivered to a customer mailbox at a UPS store in an area with rural mail delivery.
Lowercase is acceptable, but it must meet their guidelines for OCR readability. https://pe.usps.com/text/pub28/28c2_002.htm
Rather than something searching with all caps, isn't it more likely that the query/search is case-sensitive, and the data just happens to be stored/retrieved with all caps?