It could be that they mean "our API should accurately determine the country and state given arbitrary lat/lon coordinates with 6 decimals of precision", which sounds fair to me. With 6 digits, you are looking at centimeter/inch precision. I agree that the wording does sound off though.
They're using this API to sell gambling services, but they're apparently required to check that it's legal for the user to gamble.
Unrelated, I hate how GIS systems built on text search are turning geometry problems which are easy to reason about into unpredictable database problems.
> It appears that the API might be following this process:
> 1. Takes the coordinates and identifies the nearest building + street address.
> 2. Performs a textual best match query across its datasets.
> 3. Returns the first record, mixing up the fields from different locations.
The fact that the first Google autocomplete for the address "3520 S State St" happens to be the State St. in Utah, not Illinois, has absolutely nothing to do with whether the lat/lon coordinates (41.8,-87.6) are in the geographical boundary which describes Illinois and Utah.
I've heard people want such precision for proximity based services, like buying something from a vending machine in front of you by solely interfacing with your location instead of establishing a link to it.
Those already exists, but people always want it to be more precise since then you can put them more densely.