The correct fix for the guy with two locations was to remove the location_id column and create a join table from People to Locations. The correct fix for the guy outside was to alter the Location model to accomodate that, which included making US postal codes optional.

Your urge to 'fudge and hack' is natural but the professional solution is to resolve the root cause by correcting the data model, not fiddling with the data to 'just make it work'.

We agree again, that's why I wrote that they're "like freezing a bottle of water, it always grows and breaks worse in the end."