Imagine if your GPS would automatically add an extra stop at Starbucks in the morning and McDonald's around lunch and dinner time. You try and punch in directions to one grocery store and it reroutes you past a competitor who paid for placement.
It's user-hostile UX, but to mask the hostility the GPS can say "Starbucks on your route is offering 10% off bagels, for the next 10 minutes!". And similarly for the grocery store, "try Kwik-E-Mart and get a free treat!"
