Excellent question it certainly does come up. Practically speaking the more populous zip codes are all accounted for and that’s where the vast majority of deliveries go to. For example I took the census zip code data 150 miles (crow flies) outside Philly and found virtually 100% coverage.
For missing ones you have to fall back to distance based estimates and in my business that means you’re quote may be off and you’re exposed
For missing ones you have to fall back to distance based estimates and in my business that means you’re quote may be off and you’re exposed