Programmers fallacies about postcodes:
- A postcode covers a small geographic area
- A postcode is good enough to locate an end user for generating location suggestions
- A postcode will be in a single timezone
- A postcode only has a single state
- A postcode has no exclaves/enclaves

I would like you to meet 0872. Australia's largest postcode (I think), covers 3 states, has two cut outs (Warbuton and Alice Springs), and even still some mail outside of this area is routed via 0872