Totally, but there's a hidden win here. You'd only have to do this the first time.. I'd let them keep my email-address-to-physical-address relationship if it me

Totally, but there's a hidden win here. You'd only have to do this the first time.. I'd let them keep my email-address-to-physical-address relationship if it meant being surprised next time I get a post card. If it works out, suddenly they're the source of truth on physical addresses.. or something close to it. Seems like a service and dataset that has leverage. You know, but don't do anything evil with it!