Sensory triggers have been used in many contexts. Mrs Field's Cookies used to pipe the smell of fresh chocolate chip cookies into the mall breezeway from the sh

Sensory triggers have been used in many contexts. Mrs Field's Cookies used to pipe the smell of fresh chocolate chip cookies into the mall breezeway from the shop. French bakeries can be found by following your nose for a block or so. Natural gas and propane incorporate a trace amount of butadine as a warning. Laundry detergents and soaps often contain perfumes that people associate with cleanliness. Bad smells, for example, sewage odors, signal areas that should be avoided. See https://en.wikipedia.org/wiki/Odor https://en.wikipedia.org/wiki/Odor. That portable odor generating devices tied to location using GPS are being used to promote commerce is not surprising. The Dunking Donut idea of reinforcing the odorant with a fragment of commercial jingle is right out of a Bollywood movie or a Gibson novel. Welcome to the 21st centrury.