Any service that took money for rides would turn in to this. You know lyft? Before it was lyft, it was zimride. And zimride was just a way for college students to share rides places, a bit more organised than the Craigslist ride share board (which I used often)

Then zimride said “you can use that gps receiver you’ve got in your pocket to find people who need a ride near you and we’ll suggest how much gas money to split”. But pretty quickly people started just taking passengers even when not on their own trips, and lyft morphed in to…. Basically Uber.