system
Given the following post, respond as if you're commenting on Reddit:
human
Why isn't a zip code enough when entering an address, why must I give my State, City AND zip code?
gpt
I'd assume it's a 2nd check for incorrect zip codes...  IE: If you're sending a letter to Scruff McGruff in Chicago, IL 60652, and accidentally mix up your 5's and 6's and send it to Scruff McGruff Chicago, IL 50562, (Which is the zip code for Mallard, IA) they can say "Chances are, it was meant to go to Chicago, rather than Mallard, Iowa." And would therefore reduce "return to senders".