Agreed, especially when shipping, and invalid address can be expensive. We were charged $$ for each address which was "invalid"...even as simple as missing a "N

Agreed, especially when shipping, and invalid address can be expensive. We were charged $$ for each address which was "invalid"...even as simple as missing a "NE" on the street. An address lookup service was put in place, but it was done non-obtrusively. The user was prompted if the address was completely invalid, but they were allowed to ignore and continue anyway instead of stopping the order. Bad-validation certainly doesn't justify no-validation.