Invalid zip codes in classifieds..


I frequently find that people attempting to sell equipment in AG classifieds enter invalid zip codes. Is this some kind of sales tactic or do people not know their own zip codes? I get more excited about buying stuff locally so I look at the zip if it might be close and it is not uncommon to find invalid zips. What gives?
bizango1
The question is why doesn't Audiogon update their database of zip codes? How hard could that be?
Post removed 
I used to update the national online zipcode file at a major retailer. Each zipcode represents a post office.
Post offices open and they close or are merged so the master list always changes.
It's up to the seller to validate the zip specified in the ad (but dude! I'm so tired!).