Sonic and others understand that we travel to places that have Sonic even if we live in a place that doesn't have it. and when we travel having seen all of those ads we're curious. so we're more likely to check them out than if we'd never seen those ads. plus they also are on an expansion plan and so when they expand into a market where they'd been airing commercials (like here in Chicago) the ppl are primed and ready already.

i read about this w/Sonic and i think it's genius.

http://aht.seriouseats.com/archives/2008/10/good-question-why-does-sonic-advertise-on-tv-when-theres-no-sonic-near-me.html

http://jalopnik.com/322884/sonic-drive-ins-slowly-creeping-northward

^ and that last link is from 2007. i'm sure there are more locations up north now than there were then. there are several more in Chicago and STL now than then.