Dunkin' Donuts in South Korea wanted more people to drink its coffee. But it was a hard sell, with so many coffee places around. So the chain created a radio jingle and every time the ad would play on Seoul buses, a scent that smelled like fresh coffee would be sprayed (aka "flavor radio"). The idea was that when the bus would drop passengers off, they'd then go to the nearby Dunkin' Donuts for their morning cup of joe.
Apparently, it worked. Visits to stores near bus stops grew 16 percent and the chain saw a 29 percent increase in coffee sales during the campaign.
The lesson here pretty much seems to be that consumers are totally cool with being manipulated, especially if it smells good.