It's not true that zip codes are unique to a particular city and state in the United States. Where I live, for instance, several couple of cities share the same post office - and thus zip code. It does cause confusion in some instances, especially with address verification.
There have been times when I have had to put the wrong city in my address because of zip code enforcement. Fortunately, the post office does a pretty good job delivering anyway.
There have been times when I have had to put the wrong city in my address because of zip code enforcement. Fortunately, the post office does a pretty good job delivering anyway.